Light-emitting element, light-emitting-element wafer, and electronic apparatus

ABSTRACT

A light-emitting element includes a light-emitting layer, and an optical function film. The light-emitting layer is configured to include a first plane with a first electrode, a second plane with a second electrode, and a circumferential plane connecting the first and second planes, the second plane being opposing to the first plane, and the light-emitting layer being made of a semiconductor. The optical function film is configured to include a reflection layer being able to reflect light coming from the light-emitting layer, the reflection layer being provided with first and second regions, the first region covering the second plane and the circumferential plane, the second region protruding from the first region to an outside of the light-emitting layer to expose an end plane thereof.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Priority PatentApplication JP 2013-163933 filed Aug. 7, 2013, the entire contents ofwhich are incorporated herein by reference.

BACKGROUND

The present disclosure relates to a light-emitting element including asemiconductor material, a light-emitting-element wafer, and anelectronic apparatus.

There is a semiconductor light-emitting element known to include alight-emitting layer made of a semiconductor material such as AsP(arsenic phosphide) or AlGaInP (aluminum gallium indium phosphide)compound. As an example, refer to Patent Application Laid-open No.2011-66056. Such a light-emitting element is typically in the layerstructure including an n-type semiconductor layer, an active layer, anda p-type semiconductor layer. In the structure, the active layerproduces light, and the light produced by the active layer is emittedfrom a light-emission plane being a part of the surface of thelight-emitting element.

SUMMARY

With the above structure, however, there is a problem of reducedefficiency of light emission from the light-emission plane due to alight leakage from the remaining area to the outside. A difficulty inadjusting the directivity of emitted light is also a problem.

It is thus desirable to provide a light-emitting element, alight-emitting-element wafer, and an electronic apparatus with whichemitted light is provided with enhanced emission intensity and improveddirectivity.

According to an embodiment of the present disclosure, there is provideda light-emitting element that includes a light-emitting layer, and anoptical function film.

The light-emitting layer is configured to include a first plane with afirst electrode, a second plane with a second electrode, and acircumferential plane connecting the first and second planes, the secondplane being opposing to the first plane, and the light-emitting layerbeing made of a semiconductor.

The optical function film is configured to include a reflection layerbeing able to reflect light coming from the light-emitting layer, thereflection layer being provided with first and second regions, the firstregion covering the second plane and the circumferential plane, thesecond region protruding from the first region to an outside of thelight-emitting layer to expose an end plane thereof.

Such a structure allows the first region of the reflection layer toreflect light directed to the side of the circumferential plane or thesecond plane of the light-emitting layer, and the second region of thereflection layer to reflect also light directed toward the outside ofthe light-emitting layer. As a result, emitted light is enhanced inemission intensity, and improved in directivity.

Moreover, with the exposed end plane of the reflection layer, the heatdissipation is improved.

The optical function film may further include a first insulation layerformed between the light-emitting layer and the reflection layer, and asecond insulation layer formed on the reflection layer.

With the optical function film in such a structure, the first insulationlayer provides insulation between the light-emitting layer and thereflection layer, and the second insulation layer improves insulationbetween the light-emitting layer and the outside.

The second region may protrude in a direction parallel to the firstplane.

Alternatively, the second region may protrude in a direction parallel tothe circumferential plane.

With the second region as above, light directed to the circumferentialportion of the first plane is reflected by the second region so that theemission intensity is enhanced.

The light-emitting element may further include an inorganic insulationfilm configured to cover the first plane.

This allows the light-emitting layer to be covered in its entirety bythe inorganic film and the optical function film, to be stablyprotected, and to be provided with electrical insulation. Moreover, byadjusting the inorganic film to have a predetermined thickness inaccordance with a refractive index with the light-emitting layer, theemission intensity is enhanced due to interference of light.

The first plane may be in a concave-convex structure.

Such a structure allows adjustment of optical characteristics of thefirst plane, and enhancement of the emission intensity for light comingfrom the first plane being a light-emission plane.

The first plane may be formed to be larger than the second plane.

Such a structure allows size increases of the first plane being alight-emission plane, and the reflection layer to include taperedplanes. Therefore, the emission intensity from the first plane isenhanced.

The first region may include first and second reflection planes, thefirst reflection plane being opposing to the second plane, the secondreflection plane being opposing to the circumferential plane.

The second reflection plane may form a first tilt angle with the firstplane, and the circumferential plane may form a second tilt angle withthe first plane, the first tilt angle being smaller than the second tiltangle.

This allows control over emitted light in terms of emission direction,and improvement of directivity of the emitted light.

The light-emitting layer may emit red light.

In this case, the semiconductor may include at least any one of an AsPcompound semiconductor, an AlGaInP compound semiconductor, and a GaAscompound semiconductor.

According to an embodiment of the present disclosure, there is provideda light-emitting-element wafer that includes a support substrate, and aplurality of light-emitting elements.

The light-emitting elements each include a light-emitting layer, and anoptical function film.

The light-emitting layer is configured to include a first plane with afirst electrode, a second plane with a second electrode, and acircumferential plane connecting the first and second planes, the secondplane being opposing to the first plane, and the light-emitting layerbeing made of a semiconductor.

The optical function film is configured to include a first regioncovering the second plane and the circumferential plane, a second regionprotruding from the first region to an outside of the light-emittinglayer to expose an end plane thereof, and a reflection layer being ableto reflect light coming from the light-emitting layer.

The light-emitting elements are arranged on the support substrate, thesupport substrate being opposing to the second plane of thelight-emitting layer with the optical function film being sandwichedtherebetween.

With the light-emitting-element wafer, because the light-emittingelements are arranged on the support substrate, these light-emittingelements may be supplied with ease to an electronic apparatus such asdisplay apparatus.

The light-emitting-element wafer may further include an attachment layerconfigured to attach the support substrate and the plurality oflight-emitting elements.

This structure may allow easy attachment between the support substrateand the light-emitting elements.

According to an embodiment of the present disclosure, there is providedan electronic apparatus that includes a substrate formed with a drivingcircuit, and at least one first semiconductor light-emitting element.

The first semiconductor light-emitting element includes a light-emittinglayer, and an optical function film.

The light-emitting layer is configured to include a first plane with afirst electrode connected to the driving circuit, a second plane with asecond electrode connected to the driving circuit, and a circumferentialplane connecting the first and second planes, the second plane beingopposing to the first plane, and the light-emitting layer being made ofa semiconductor.

The optical function film is configured to include a first regioncovering the second plane and the circumferential plane, a second regionprotruding from the first region to an outside of the light-emittinglayer to expose an end plane thereof, and a reflection layer being ableto reflect light coming from the light-emitting layer.

The first semiconductor light-emitting element is arranged on thesubstrate, the substrate being opposing to the second plane with theoptical function film being sandwiched therebetween.

The first semiconductor light-emitting element and other firstsemiconductor light-emitting elements may emit red light with.

The electronic apparatus may further include a plurality of secondsemiconductor light-emitting elements that emit blue right, and aplurality of third semiconductor light-emitting elements that emit greenlight.

The first, second, and third semiconductor light-emitting elements maybe arranged on the substrate.

This allows provision of an electronic apparatus such as displayapparatus having desired display characteristics using a plurality offirst semiconductor elements.

As described above, according to the embodiments of the presentdisclosure, provided are a light-emitting element, alight-emitting-element wafer, and an electronic apparatus with whichemitted light is with enhanced emission intensity and improveddirectivity.

These and other objects, features and advantages of the presentdisclosure will become more apparent in light of the following detaileddescription of best mode embodiments thereof, as illustrated in theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic plan view of a light-emitting-element waferaccording to a first embodiment of the present disclosure;

FIG. 2 is a schematic cross-sectional view of the light-emitting-elementwafer of FIG. 1;

FIG. 3 is a schematic cross-sectional view of a light-emitting elementof FIG. 1, showing the structure thereof;

FIG. 4 is a graph showing FFPs (Far Field Patterns) when emitted lightis viewed from a plurality of directions orthogonal to the normal of afirst plane, and showing the results in examples according to the firstembodiment;

FIG. 5 is a graph showing FFPs when emitted light is viewed from aplurality of directions orthogonal to the normal of the first plane, andshowing the results in comparison examples;

FIG. 6 is a schematic diagram for illustrating a radiation angle θ inthe graphs of FIGS. 4 and 5, and an angle φ relative to the direction ofviewing the emitted light;

FIGS. 7A and 7B are each a diagram illustrating the effect affecting thedirectivity of light with a first inorganic film of FIG. 1, and morespecifically, FIG. 7A is a schematic cross-sectional view of a main partof the light-emitting element of FIG. 1, and FIG. 7B is a diagramshowing a correlation between the first inorganic film in thelight-emitting element (a refractive index N, and a thickness t (nm)thereof) and a distribution of light directivity;

FIGS. 8A and 8B are each a graph exemplarily showing an FFP with respectto the radiation angle θ;

FIG. 9 is a flowchart of a manufacturing method for thelight-emitting-element wafer of FIG. 1;

FIGS. 10A to 10C are each a schematic cross-sectional view of thelight-emitting-element wafer of FIG. 1, showing the manufacturing methodtherefor;

FIGS. 11A and 11B are each a schematic cross-sectional view of thelight-emitting-element wafer, showing the manufacturing method therefor;

FIGS. 12A and 12B are each a schematic cross-sectional view of thelight-emitting-element wafer, showing the manufacturing method therefor;

FIGS. 13A and 13B are each a schematic cross-sectional view of thelight-emitting-element wafer, showing the manufacturing method therefor;

FIGS. 14A and 14B are each a schematic cross-sectional view of thelight-emitting-element wafer, showing the manufacturing method therefor;

FIGS. 15A and 15B are each a schematic cross-sectional view of thelight-emitting-element wafer, showing the manufacturing method therefor;

FIGS. 16A and 16B are each a schematic cross-sectional view of thelight-emitting-element wafer, illustrating a process of forming anoptical function film in the manufacturing method therefor;

FIGS. 17A and 17B are each a schematic cross-sectional view of thelight-emitting-element wafer, illustrating the process of forming theoptical function film in the manufacturing method therefor;

FIGS. 18A and 18B are graphs showing the results of a comparison betweena reflection layer formed by lifting-off and a reflection layer formedby wet etching, and more specifically, FIG. 18A is a graph showing therelationship between the width of a first separation groove and that ofa second aperture portion in the reflection layer between the elementsadjacent to each other, and FIG. 18B is a graph showing a degree ofmisalignment of an element separation mask with respect to thereflection layer in the plane of the light-emitting-element wafer;

FIG. 19 is a schematic plan view of a display apparatus (electronicapparatus) using the light-emitting element of FIG. 1;

FIG. 20 is a flowchart of a manufacturing method for the displayapparatus of FIG. 19;

FIG. 21 is a schematic plan view of the display apparatus, showing themanufacturing method therefor;

FIGS. 22A to 22C are each a schematic cross-sectional view of thedisplay apparatus, showing the manufacturing method therefor;

FIGS. 23A to 23C are each a schematic cross-sectional diagram showing acase with a displacement of center of gravity between an attachmentlayer and a light-emitting layer in a process of moving thelight-emitting element from a support substrate onto a first transfersubstrate;

FIG. 24 is a graph showing the relationship between a degree ofmisalignment of an element separation mask and a degree of displacementof a transfer position, and more specifically, showing the results of acomparison between a reflection layer whose end plane is exposed(example of experiment 1) and a reflection layer whose end plane is notexposed (example of experiment 2);

FIG. 25 is a schematic cross-sectional view of a light-emitting-elementwafer according to a second embodiment of the present disclosure;

FIGS. 26A to 26C are each a schematic cross-sectional view of thelight-emitting-element wafer of FIG. 25, showing a manufacturing methodtherefor;

FIGS. 27A to 27C are each a schematic cross-sectional view of thelight-emitting-element wafer, showing the manufacturing method therefor;

FIGS. 28A and 28B are each a schematic cross-sectional view of thelight-emitting-element wafer, showing the manufacturing method therefor;

FIGS. 29A and 29B are each a schematic cross-sectional view of thelight-emitting-element wafer, showing the manufacturing method therefor;

FIGS. 30A and 30B are each a schematic cross-sectional view of thelight-emitting-element wafer, showing the manufacturing method therefor;

FIG. 31 is a schematic cross-sectional view of a light-emitting-elementwafer according to a third embodiment of the present disclosure;

FIGS. 32A 32C are each a schematic cross-sectional view of thelight-emitting-element wafer of FIG. 31, showing a manufacturing methodtherefor;

FIGS. 33A to 33C are each a schematic cross-sectional view of thelight-emitting-element wafer, showing the manufacturing method therefor;

FIGS. 34A to 34C are each a schematic cross-sectional view of alight-emitting-element wafer in a reference example according to thethird embodiment of the present disclosure, showing a manufacturingmethod therefor;

FIGS. 35A to 35C are each a schematic cross-sectional view of thelight-emitting-element wafer of FIGS. 34A to 34C, showing themanufacturing method therefor;

FIG. 36 is a schematic cross-sectional view of a light-emitting element(light-emitting-element wafer) in a modified example according to thethird embodiment of the present disclosure; and

FIG. 37 is a schematic cross-sectional view of thelight-emitting-element wafer of FIG. 36, showing a manufacturing methodtherefor.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be describedwith reference to the drawings.

First Embodiment

FIG. 1 is a schematic plan view of a light-emitting-element wafer 100according to a first embodiment of the present disclosure, and FIG. 2 isa schematic cross-sectional view of the light-emitting-element wafer100. Described below is the structure of the light-emitting-elementwafer 100 according to this embodiment. In the drawings, X- and Y-axesare orthogonal to each other, i.e., in-plane direction of thelight-emitting-element wafer 100, and a Z-axis is orthogonal to the X-and Y-axes, i.e., the thickness and vertical direction of thelight-emitting-element wafer 100.

[Semiconductor Light-Emitting-Element Wafer]

The light-emitting-element wafer 100 includes a support substrate 10, aplurality of light-emitting elements 1, an attachment layer 30, and aseparation groove section 60. In the light-emitting-element wafer 100,the light-emitting elements 1 are arranged on the support substrate 10.As will be described later, the light-emitting-element wafer 100 in thisembodiment is for providing the light-emitting elements 1, which are tobe mounted on electronic apparatuses including display apparatuses,lighting fixtures, or others.

The support substrate 10 includes a surface 11 on which thelight-emitting elements 1 are disposed, and is a 2- to 12-inch wafer,for example. The support substrate 10 is made of a material that showshigh transmittance for a laser wavelength used in a manufacturingprocess that will be described later, for example. Such a material isexemplified by sapphire (Al₂O₃), quartz (SiO₂), or glass.

The light-emitting elements 1 are arranged on the support substrate 10along the X- and Y-axis directions.

The attachment layer 30 attaches together the support substrate 10 andthe light-emitting elements 1. The attachment layer 30 is disposedbetween the support substrate 10 and an external connection terminal 730in each of the light-emitting elements 1 that will be described later.The attachment layer 30 has the thickness of 0.2 μm to 2 μm inclusive,and is made of a thermoplastic resin material or others that areadhesive such as polyimide. The attachment layer 30 as above may beeasily separated from the support substrate 10 by the action ofablation, which occurs when the thermoplastic resin material or othersare heated and evaporated by irradiation of laser light with apredetermined wavelength, for example.

The material of the attachment layer 30 is not restricted to the above,and may include an ultraviolet curing resin, an adhesive sheet, anadhesive material, or others.

The light-emitting elements 1 adjacent to each other are separated bythe separation groove section 60. That is, the separation groove section60 is formed with a depth reaching the surface 11 of the supportsubstrate 10 from an inorganic film 40 of each of the light-emittingelements 1 that will be described later, thereby separating thelight-emitting elements 1. In the below, the light-emitting elements 1are sometimes simply referred to as “elements 1”.

[Light-Emitting Element]

The light-emitting elements 1 are each a light-emitting diode (LED) inthe structure with layers of semiconductor compounds. In thisembodiment, the light-emitting elements 1 are arranged on the supportsubstrate 10. The size of each of the light-emitting elements 1 isarbitrarily determined considering the size of the support substrate 10or the configuration of an electronic apparatus on which thelight-emitting elements 1 are mounted, e.g., the length along the X-axisdirection is 1 μm to 300 μm inclusive, the length along the Y-axisdirection is 1 μm to 300 μm inclusive, and the height along the Z-axisdirection is 1 μm to 20 μm inclusive.

FIG. 3 is a schematic cross-sectional view of the light-emitting element1, showing the structure thereof. The light-emitting element 1 includesa light-emitting layer 20, the inorganic film 40, and an opticalfunction film 50.

The light-emitting layer 20 is a semiconductor, including first andsecond planes 201 and 202, and a circumferential plane 203. The firstplane 201 includes a first electrode 710, and the second plane 202includes a second electrode 720. The circumferential plane 203 connectstogether the first and second planes 701 and 702.

The inorganic film 40 functions as an inorganic insulation film thatcovers the first plane 201.

The optical function film 50 functions with a reflection layer 53 thatreflects light coming from the light-emitting layer 20.

In the below, the structure elements in the light-emitting element 1 areeach described.

[Light-Emitting Layer]

In this embodiment, the light-emitting layer 20 is in the structure withsemiconductor layers that emit red light, and includes GaAs and AlGaInPsemiconductor compounds, for example. The light-emitting layer 20includes a first semiconductor layer 21 of a first conductivity type, anactive layer 23 formed on the first semiconductor layer 21, and a secondsemiconductor layer 22 of a second conductivity type formed on theactive layer 23. In this embodiment, the first conductivity type isassumed to be n, and the second conductivity type is assumed to be p,but this is not restrictive.

The light-emitting layer 20 includes the first plane 201, the secondplane 202 provided on the side opposite to the first plane 201, and thecircumferential plane 203 connecting together the first and secondplanes 201 and 202.

The first and second planes 201 and 201 are disposed to face to eachother in the Z-axis direction, and the light-emitting layer 20 has theentire thickness of about 1 μm to 20 μm inclusive, for example.

The light-emitting layer 20 is not particularly restricted in shape. Asan example, the first plane 201 is formed to be larger than the secondplane 202 in the planar view from the Z-axis direction like a squarefrustum. In this case, the cross-sectional area of the light-emittinglayer 20 orthogonal to the Z-axis direction is gradually increased fromthe second plane 202 toward the first plane 201. The circumferentialplane 203 is so configured as to include four tapered planes.

The first plane 201 includes a connection region 2011 formed with thefirst electrode 710, and a light extraction region 2012 formed in afirst concave-convex structure (concave-convex structure) 210. Theconnection region 2011 occupies the center portion of the first plane201, and the light extraction region 2012 is so disposed as to enclosethe connection region 2011. The connection region 2011 is not restrictedin position and shape, but may be in the oval shape, or may be providedlike an island at several positions, for example.

The first concave-convex structure 210 may be changed as appropriate soas to provide the emitted light with desired optical characteristics. Asexemplarily shown in FIG. 3, the first concave-convex structure 210 maybe in the shape of a prism with ridge lines, or may include groove-likeconcave portions formed on a flat plane (the remaining portions areconvex) (refer to FIGS. 10A to 15B).

The expression “the first plane 201 is substantially orthogonal to theZ-axis direction” indicates that a reference plane 201 s of the firstplane 201 is substantially orthogonal to the Z-axis direction. Thereference plane 201 s of the first plane 201 is assumed to be a virtualplane including vertex portions (vertex planes) of a plurality of convexportions in the first concave-convex structure 210 by referring to FIG.3.

The second plane 202 includes a connection region 2021, and a reflectionregion 2022 to enclose the connection region 2021. The connection region2021 is formed with the second electrode 720, and occupies the centerportion of the second plane 202. The reflection region 2022 is coveredby the optical function film 50.

From the light-emitting layer 20, light produced by the active layer 23is emitted via the light extraction region 2012 of the first plane 201.In this embodiment, in the above-mentioned two respects, i.e., in therespect that the circumferential plane 203 is configured to include fourtapered planes, and is covered by the reflection layer 53 of the opticalfunction film 50 that will be described later, and in the other respectthat the light extraction region 2012 of the first plane 201 is in thefirst concave-convex structure 210, the light is reflected upward in theZ-axis direction so that the efficiency of light emission is improved,and the directivity of light is controlled. In the below, the expressionof “upward in the Z-axis direction” is sometimes referred to as “towardthe front of the light-emitting element 1”.

The first semiconductor layer 21 is in the layer structure including afirst contact layer 211, and a first cladding layer 212. The firstcontact layer 211 is connected with the second electrode 720, and thearea thereof is substantially the same as that of the second electrode720 when it is viewed from the Z-axis direction. The first contact layer211 is made of a material allowing Ohmic contact with the secondelectrode 720, e.g., n-type GaAs (gallium arsenide). The first claddinglayer 212 is formed on the first contact layer 211, and occupiesentirely the second plane 202 when it is viewed from the Z-axisdirection. That is, the exposed surface of the first cladding layer 212serves as a reflection region 2022 of the second plane 202. The firstcladding layer 212 includes n-type AlGaInP, for example.

The active layer 23 is in the multiquantum well structure including aplurality of well layers and a plurality of barrier layers, and is ableto emit light with a predetermined wavelength. The well layers and thebarrier layers are made of semiconductor materials of differentcompositions. The active layer 23 in this embodiment is able to emit redlight with an emission wavelength of about 500 to 700 nm. The activelayer 23 includes about 10 to 20 well layers including GaInP (galliumindium phosphide), and 10 to 20 barrier layers including AlGaInP, forexample. These well and barrier layers are alternately disposed.

The second semiconductor layer 22 is in the layer structure including asecond cladding layer 221, and a second contact layer 222. The secondcladding layer 221 is formed on the active layer 23, and includes p-typeAlGaInP, for example. The second contact layer 222 is formed on thesecond cladding layer 221, and is connected with the first electrode710. The second contact layer 222 occupies entirely the first plane 201when it is viewed from the Z-axis direction. The surface of the secondcontact layer 222 not connected with the first electrode 710 is exposed,and serves as the light extraction region 2012 of the first plane 201.The second contact layer 222 is made of a material allowing Ohmiccontact with the first electrode 710, e.g., P-type GaP (galliumphosphide).

Alternatively, in the respective first and second semiconductor layers21 and 22, the above-mentioned layers may include therebetween anotherlayer as appropriate. As an example, in the second semiconductor layer22, the active layer 23 and the second cladding layer 221 may includetherebetween a protection layer including undoped AlGaInP. Thisprotection layer may prevent diffusion of a doping agent in the secondcladding layer 221 or others to the side of the active layer 23. Herein,the material described for each of the layers in the light-emittinglayer 20 is an example, and may be selected as appropriate consideringthe structure of the light-emitting element 1 or desired light emissioncharacteristics.

The first electrode 710 is formed to the connection region 2011 of thefirst plane 201, and is connected to the second contact layer 222. Thatis, the surface of the first electrode 710 serves as the connectionregion 2011 of the first plane 201. The first electrode 710 is notparticularly restricted in shape, and may be in the oval, circular, orrectangular shape with the length of the minor axis being about 1 to 10μm along the X-axis direction, and the length of the major axis beingabout 1 to 10 μm along the Y-axis direction, for example. The thicknessof the first electrode 710 may be 200 to 600 μm, for example. The firstelectrode 710 may be made of a metallic material including Ti(titanium), Pt (platinum), Au (gold), Ge (germanium), Ni (nickel), andPd (palladium), or an alloy or a laminate thereof, or a transparentconductive material including ITO (indium-tin oxide), for example.

The second electrode 710 is formed to the connection region 2021 of thesecond plane 202, and is connected to the first contact layer 211. Thatis, the surface of the second electrode 720 serves as the connectionregion 2021 of the second plane 202. The second electrode 720 is notparticularly restricted in shape, and may be in the oval, circular, orrectangular shape, for example. The thickness of the second electrode720 may be 200 to 600 μm, for example. The second electrode 720 may bemade of a metallic material including Ti, Pt, Au, Ge, Ni, and Pd, or analloy or a laminate thereof, or a transparent conductive materialincluding ITO, for example.

[Inorganic Film]

The inorganic film 40 is so formed as to cover the light extractionregion 2012 of the first plane 201. More specifically, the inorganicfilm 40 is formed on the first electrode 710 (the connection region2011), and includes a connection hole 420 facing the first electrode710. The inorganic film 40 has the thickness of 200 μm to 600 μminclusive, and more desirably, the thickness of 300 μm to 500 μminclusive, for example.

The inorganic film 40 is in a second concave-convex structure 410, andincludes a first end portion 41. The second concave-convex structure 410is formed to conform to the first concave-convex structure 210 of thefirst plane 201, and the first end portion 41 is formed at thecircumferential edge of the second concave-convex structure 410. Thefirst end portion 41 has a flat plane formed to be parallel to the firstplane 201, and protrudes toward the outside of the first plane 201. Theexpression of “(a flat plane) formed to be parallel to the first plane201” means that the first end portion 41 is formed to be parallel to thereference plane 201 s of the first plane 201.

The inorganic film 40 is light-transmissive, and is made of siliconnitride (hereinafter, SiN) with the refractive index of 1.9 to 2.3inclusive, silicon oxide such as SiO₂, or a laminate of SiN and SiO₂,for example. Alternatively, the inorganic film 40 may be made of aninsulation material such as TiN (titanium nitride), TiO₂ (titaniumdioxide), or others. This provides insulation to the first plane 201 ofthe light-emitting layer 20, and allows the inorganic film 40 to serveas a protection film for the first plane 201. As will be describedlater, with the inorganic film 40 having the predetermined thickness andrefractive index, the light-emitting element 1 may emit light withenhanced intensity toward the front thereof.

[Optical Function Film]

The optical function film 50 is so formed as to cover as a whole thesecond plane 202 and the circumferential plane 203 of the light-emittinglayer 20. The optical function film 50 reflects light coming from thelight-emitting layer 20 toward the side of the first plane 201, therebycontributing to improve the efficiency of light emission.

To be more specific, the optical function film 50 is formed to cover thereflection region 2022 on the second plane 202, and on thecircumferential plane 203, is formed to entirely cover thecircumferential plane 203. The thickness of the optical function film 50on the second plane 202 is 0.1 μm or more, and the thickness of theportion thereof along the circumferential plane 203 is 0.1 μm or more,for example.

The optical function film 50 includes a second end portion 510 thatprotrudes toward the outside of the light-emitting layer 20. In thisembodiment, the second end portion 510 protrudes in a direction parallelto the first plane 201 of the light-emitting layer 20. That is, thesecond end portion 510 serves as a flange portion of the opticalfunction film 50, i.e., is bent to be parallel to the first plane 201,and is formed to conform to the first end portion 41 of the inorganicfilm 40. The thickness of the second end portion 510 is 0.2 μm to 5 μminclusive, for example.

As to the height of the above structure along the Z-axis direction fromthe surface 11 of the support substrate 10, the height to the second endportion 510 of the optical function film 50, i.e., height H2, is lowerthan the height to the surface of the inorganic film 40 at the first endportion 41, i.e., height H1 (refer to FIG. 2).

The optical function film 50 includes the reflection layer 53, a firstinsulation layer 51, and a second insulation layer 52. The reflectionlayer 53 is able to reflect light coming from the light-emitting layer20. The first insulation layer 51 is formed between the light-emittinglayer 20 and the reflection layer 53, and the second insulation layer 52is formed on the reflection layer 53. That is, the optical function film50 is in the layer structure including the layers in order on thelight-emitting layer 20, i.e., the first insulation layer 51, thereflection layer 53, and the second insulation layer 52.

The first insulation layer 51 covers the second plane 202, starting fromthe reflection region 2022 and the circumferential plane 203 up to thesecond end portion 510 directly below the first end portion 41. On theother hand, the second insulation layer 52 is formed to the region wherethe first insulation layer 51 is already formed when it is viewed fromthe Z-axis direction. The first and second insulation layers 51 and 52may be made of silicon oxide such as SiO₂, or SiN (silicon nitride),TiN, or TiO₂, or any other inorganic insulation materials, or a laminatethereof.

The reflection layer 53 includes an aperture portion 534 larger than aconnection hole 540 that will be described later, and is formed betweenthe first and second insulation layers 51 and 52. The reflection layer53 serves to reflect light coming from the light-emitting layer 20toward the first plane 201. This means that the reflection layer 53 maybe made of a material with high efficiency for reflection of lightcoming from the light-emitting layer 20.

In this embodiment, the reflection layer 53 is made of a metallicmaterial including Al (aluminum), Au, Ti, Cu (copper), Ni, Ag (silver),and others, or an alloy or a laminate thereof, for example.

The reflection layer 53 is formed between the first and secondinsulation layers 51 and 52. This provides insulation to the reflectionlayer 53 from the light-emitting layer 20 and the outside of thelight-emitting element 1. That is, this allows the reflection layer toelectrically float.

The reflection layer 53 includes first and second regions 531 and 532.The first region 531 covers the second plane 202 and the circumferentialplane 203, and the second region 532 protrudes from the first region 531toward the outside of the light-emitting layer 20. The second region 532is formed inside of the second end portion 510, and in this embodiment,protrudes in a direction parallel to the first plane 201 (the referenceplane 201 s of the first plane 201).

By the reflection layer 53 including the second region 532, the lightfound its way into the first end portion 41 may be reflected upward inthe Z-axis direction before emission. As a result, the light-emittingelement 1 may emit light with enhanced intensity toward the frontthereof.

The first region 531 of the reflection layer 53 includes a firstreflection plane 5311 opposing to the second plane 202, and a secondreflection plane 5312 opposing to the circumferential plane 203. In thisembodiment, the first region 531 is formed in such a manner that a firsttilt angle between the second reflection plane 5312 and the referenceplane 201 s of the first plane 201 is nearly the same as a second tiltangle between the circumferential plane 203 and the reference plane 201s of the first plane 201.

The connection hole 540 is formed by the first and second insulationlayers 51 and 52. That is, from the inner circumferential plane of theconnection hole 540, the first and second insulation layers 51 and 52are exposed but not the reflection layer 53. This provides insulationbetween the reflection layer 53 and the second electrode 720.

The reflection layer 53 includes an end plane 532 s, which is exposedfrom the end plane of the second end portion 510 in the second region532. This accordingly improves heat dissipation of the light-emittingelement 1.

In this embodiment, the first and second end portions 41 and 510 eachhave an end plane parallel to the Z-axis direction, and these end planesare formed in the same plane.

The light-emitting element 1 in this embodiment includes the externalconnection terminal 730 for connection with the second electrode 720exposed from the connection hole 540.

[External Connection Terminal]

The external connection terminal 730 is disposed between the attachmentlayer 30 and the optical function film 50. The external connectionterminal 730 covers the optical function film 50 and the secondelectrode 720 for connection with the second electrode 720, and is inthe rectangular shape substantially the same size as the firstreflection plane 5311 of the optical function film 50 when it is viewedfrom the Z-axis direction. The thickness of the external connectionterminal 730 is not particularly restrictive, but may be 0.1 μm to 0.5μm inclusive, for example. The external connection terminal 730 is madeof a metallic material including Al, Au, Ti, or others, or an alloy or alaminate thereof.

Alternatively, as shown in FIG. 3, a resin film 732 may be formed so asto fill a concave portion 733 of the external connection terminal 730formed by the connection hole 540. This resin film 732 is made of anadhesive resin material, for example. The resin film 732 may be formednot only in the concave portion 733 but also over the region where theexternal connection terminal 730 is formed (refer to a resin R3 in FIGS.15A and 15B).

The light-emitting elements 1 are each so disposed that the second plane202 of the light-emitting layer 20 faces the support substrate 10 viathe optical function film 50, and are all attached onto the supportsubstrate 10 via the attachment layer 30.

Such light-emitting elements 1 are each provided with the opticalfunction film 50 including the reflection layer 53, which covers thesecond plane 202 and the circumferential plane 203. The light emittedfrom the active layer 23 toward the second plane 202 and thecircumferential plane 203 is thus reflected by the first region 531 ofthe reflection layer 53, and even if the light finds its way into thefirst end portion 41 of the inorganic film 40, the light is reflected bythe second region 532 of the reflection layer 53. This accordinglyimproves the efficiency of light emission toward the front of thelight-emitting element 1. Moreover, as will be described below, thereflection layer 53 may improve the directivity of emitted light.

[Effect of Reflection Layer on Directivity of Light]

FIGS. 4 and 5 are each a graph showing FFPs (Far Field Patterns) whenemitted light is viewed from a plurality of directions orthogonal to thenormal of the first plane 201, i.e., the direction parallel to theZ-axis direction. In the graph, the horizontal axis indicates aradiation angle θ, and the vertical axis indicates the intensity ofemitted light (standardized intensity when the intensity of θ=0° is 1).FIG. 4 shows the results of examples in this embodiment in which thereflection film 53 is in use, and FIG. 5 shows the results of comparisonexamples in which no reflection film is in use.

FIG. 6 is a schematic diagram for illustrating the radiation angle θ inthe graphs of FIGS. 4 and 5, and an angle φ relative to the direction ofviewing the emitted light. As shown in FIG. 6, the radiation angle θ isrelative to the normal of the light-emission plane, and in thisembodiment, is relative to the Z-axis direction orthogonal to the firstplane 201. The direction of viewing the emitted light is defined by theangle φ relative to the reference direction in the XY plane, which isparallel to the first plane 201. Herein, the reference direction is aspecific direction, e.g., Y-axis direction, parallel to the first plane201 being a light-emission plane, i.e., 0°. That is, the graphs of FIGS.4 and 5 show the results when the emitted light is viewed from theangles φ=0°, 45°, 90°, and 135°.

In FIG. 4, the FFPs are almost in the same shape irrespective of theangle φ. In FIG. 5, unlike the results in FIG. 4, the FFPs vary in shapedepending on the angle φ.

Generally, for the FFP of the emitted light, Lambertian is considereddesirable. Lambertian is a description of an FFP of emitted light, andmeans a light distribution in which, when the radiation intensity isdivided by the cosine of the radiation angle θ (cos θ), an FFP ofemitted light on a certain light-emission plane takes given valuesirrespective of the angle φ of viewing the emitted light. When an FFP ofemitted light is Lambertian, for example, the radiation intensity takesa maximum value toward the front of the light-emitting element 1 (θ=0°),and tends to be reduced with an increase of the absolute value of theradiation angle θ. With the FFP of the emitted light being Lambertian asabove, the emitted light is uniform in all directions with the reducedviewing angle dependency thereof. For reference, FIGS. 4 and 5respectively show the FFPs that take given values when the radiationintensity is divided by cos θ.

Hereinafter, such FFPs are referred to as reference FFPs.

That is, the FFPs of FIG. 5 vary depending on the angle φ of viewing theemitted light, and thus is not Lambertian. On the other hand, the FFPsof FIG. 4 are all in the shape similar to the reference FFP, and thus isLambertian. This accordingly confirms that, with the reflection layer53, the emitted light has reduced viewing angle dependency in terms oflight-emission intensity, the FFPs are ideal Lambertian, and the emittedlight is improved in directivity.

Also in this embodiment, the light-emitting layer 20 except for theconnection regions 2011 and 2021 is covered on the surface not only bythe optical function film 50 but also by the inorganic film 40. Thisprovides insulation to the light-emitting layer 20, and ensures thelight-emitting layer 20 to be physically and chemically stable.

As to the inorganic film 40, by adjusting the thickness and refractiveindex thereof, the emitted light from the light-emitting element 1 maybe adjusted in directivity by utilizing interference of light with apredetermined wavelength. Described in the below is how the inorganicfilm 40 affects the directivity of the emitted light.

[Effect of Inorganic Film on Directivity of Light]

FIG. 7A is a schematic cross-sectional view of the light-emitting layer20 of the light-emitting element 1, and FIG. 7B is a diagram showing acorrelation between the inorganic film 40 (a refractive index N and athickness t (nm) thereof) and the distribution of light directivity. Tobe more specific, the horizontal axis indicates a value of Nt/λ when theemitted light has a wavelength of λ (nm), and the vertical axisindicates the ratio of an actual radiation intensity to a radiationintensity when the FFP of the emitted light is Lambertian with theradiation angle θ of 45°. Hereinafter, such a ratio is referred to asLambertian curve ratio.

In FIG. 7B, the distribution of the Lambertian curve ratio shows a valuechange in the cycle of about Nt/λ=½ due to the influence of lightinterference. More specifically, when Nt/λ is about 1.5, i.e., 6/4(indicated by B), the curve is in the upward convex shape with themaximum value at the top, when Nt/λ is about 1.25, i.e., 5/4 (indicatedby A), the curve is in the downward convex shape, and when Nt/λ is about1.79, i.e., 7/4+0.05 (indicated by C), the curve is in the downwardconvex shape with the minimum value at the bottom.

FIGS. 8A and 8B are each a graph showing an FFP with respect to theradiation angle θ. More specifically, FIG. 8A exemplarily shows the caseof B with the maximum value in the graph of FIG. 7B, and FIG. 8Bexemplarily shows the case of C with the minimum value in the graph ofFIG. 7B together with the case of A. For reference, FIGS. 8A and 8B eachshow an FFP being Lambertian by a grayish line.

As shown in FIG. 8A, in the case of B, the radiation intensity is higherthan that in the Lambertian FFP in a range from −70<θ<70, and thelight-emission intensity toward the front of the light-emitting element1 is relatively reduced. As shown in FIG. 8B, on the other hand, in thecases of A and B, the radiation intensity is generally lower than thatin the Lambertian FFP, and the light-emission intensity toward the frontof the light-emitting element 1 is relatively enhanced.

Therefore, for increasing the light-emission intensity toward the frontof the light-emitting element 1, the value of Nt/λ in the inorganic film40 may be adjusted to be A or C in the downward-convex curve as in thegraph of FIG. 7B, for example. That is, considering the value of Nt/λand the cycle of change thereof at A and C, the factors may be adjustedto satisfy Equation 1 below, i.e., the factors of N (refractive index ofthe inorganic film 40), t (thickness of the inorganic film 40), and λ(wavelength of emitted light from the light-emitting layer 20).

Nt/λ=(x+1)/4±0.15 (x=2, 4, 6, and 8)  1

In this embodiment, λ may be adjusted to be about 630 (nm), for example.When the inorganic film 40 is made of SiN, the refractive index thereoftakes a value of 2.0≦N≦2.1, for example. Accordingly, when N=2.0, thethickness t of the inorganic film 40 may be adjusted to be 141.75 (nm)when x=2, to be 393.75 (nm) when x=4, to be 552.25 (nm) when x=6, and tobe 708.75 (nm) when x=8. Such a thickness adjustment may improve thelight-emission intensity toward the front of the light-emitting element1.

With Equation 1 as above, by selecting the material for the inorganicfilm 40 and by adjusting the thickness thereof based on the wavelengthof light from the light-emitting layer 20, the emitted light from thelight-emitting layer 20 may be improved in light-emission intensitytoward the front of the light-emitting element 1 due to constructiveinterference of light with a predetermined wavelength. As an example,Equation 1 may be satisfied with the inorganic film 40 in the layerstructure of SiN or SiN and SiO₂ with 1.9≦N≦2.3, more desirably2.0≦N≦2.1, and with the inorganic film 40 having the thickness of200≦t≦600, more desirably 300≦t≦500. With such adjustments, theproductivity of the inorganic film 40 is maintained, and thelight-emitting element 1 is improved in directivity.

Described next is a manufacturing method for the light-emitting-elementwafer 100 in this embodiment.

[Manufacturing Method for Light-Emitting-Element Wafer]

FIG. 9 is a flowchart of a manufacturing method for thelight-emitting-element wafer 100 in this embodiment, and FIGS. 10A to15B are each a schematic cross-sectional view of thelight-emitting-element wafer for illustrating the manufacturing methodtherefor. In the below, a description is given by referring to thesedrawings.

First of all, a light-emitting layer 20 a is formed on a first substrate10 a (ST101). In this example, on the first substrate 10 a, layers inthe light-emitting layer 20 a are each formed by crystal growth usingMetal Organic Chemical Vapor Deposition (MOCVD). The first substrate 10a is a wafer made of gallium arsenide (GaAs), and the crystal surfacethereof formed with the light-emitting layer 20 a is C-plane (0001), forexample.

As described above, on the first substrate 10 a, a plurality of elementregions 1 a are defined along the X- and Y-axis directions to correspondto the elements 1. The element regions 1 a are typically defined byvirtual boundaries L.

The layers formed in order on the first substrate 10 a by crystal growthinclude a stop layer 214 a of a first conductive type, a first contactlayer 211 a, and a first cladding layer 212 a. The stop layer 214 afunctions as an etching stop layer when the first substrate 10 a isremoved, and may be made of a material that ensures a predeterminedetching selection ratio or more with the first substrate 10 a. Among theabove layers, because the stop layer 214 a is removed in the laterprocess together with the first substrate 10 a, the first contact layer211 a and the first cladding layer 212 a are included in the firstsemiconductor layer 21 of the light-emitting element 1.

Thereafter, a multiquantum well layer 23 a is formed. This multiquantumwell layer 23 a includes 10 to 20 well layers and 9 to 20 barrier layersthat are alternately disposed, for example. The resulting multiquantumwell layer 23 a configures the active layer 23 of the light-emittingelement 1.

On the multiquantum well layer 23 a, layers are formed in order bycrystal growth, i.e., a second cladding layer 221 a of a secondconductive type, and a second contact layer. The second contact layer isnot shown in FIGS. 10A to 15B. The second cladding layer 221 a and thesecond contact layer are included in the second semiconductor layer 22of the light-emitting element 1.

Note that the light-emitting layer 20 a is not restricted to the abovestructure, and may be changed as appropriate.

Next, as shown in FIG. 10A, a first plane 201 a is formed with a firstconcave-convex structure 210 a (ST102). The first concave-convexstructure 210 a is formed by photolithography, reactive ion etching(RIE), or others. In this process, the first concave-convex structure210 a may not be formed by using a mask or others (not shown) to cover aconnection region 2011 a at the center of the element region 1 a, and aboundary region 610 a between the element regions 1 a. In the resultingstructure, this may make flat both the connection region 2011 a wherethe first electrode 710 a is formed in the next process, and theboundary region 610 a where the first end portion 41 and the separationgroove section 60 are formed later.

As described above, the first concave-convex structure 210 a of thelight-emitting layer 20 a is formed immediately after the crystal growthof the light-emitting layer 20 a. This obtains the first concave-convexstructure 210 a in a desired shape with good accuracy, thereby beingable to improve the emission intensity and control the directivity oflight.

Next, as shown in FIG. 10B, the connection region 2011 a of the firstplane 201 a is formed with the first electrode 710 a (ST103). The firstelectrode 710 a is arbitrarily formed by sputtering, vapor deposition,ion plating, plating, or others, and is patterned in a predeterminedshape such as oval, for example. This first electrode 710 a is formed atleast one to each of the element regions 1 a.

As shown in FIG. 10C, the first plane 201 a including the firstelectrode 710 a is formed thereon with an inorganic film 40 a (ST104).The inorganic film 40 a is made of SiN, TiO₂, SiO₂, SiON (siliconoxynitride), NiO (nickel oxide), or AlO (aluminum oxide), or a laminatefilm thereof.

The inorganic film 40 a is substantially uniform in thickness to conformto the first plane 201 a. That is, in this process, the secondconcave-convex structure 410 a is formed by conforming to the firstconcave-convex structure 210 a.

Next, a second substrate 10 b is attached onto the inorganic film 40 ato be freely separated therefrom via a temporary attachment layer 31 a(ST105). In this embodiment, the temporary attachment layer 31 a is inthe layer structure including a first resin film 311 a, a bonding layer312 a, and a second resin film 313 a. FIG. 11A shows the inverted(upside-down) structure of FIG. 10C in which the first substrate 10 a isin the upper portion of the drawing.

First of all, as shown in FIG. 11A, the first resin film 311 a is formedby coating or others on the inorganic film 40 a. Next, the bonding layer312 a is affixed on the first resin film 311 a. The bonding layer 312 ais a resin-made adhesive sheet or made of an adhesive material, forexample. The second resin film 313 a is formed on the bonding layer 312a by coating, for example.

The first and second resin films 311 a and 313 a are each made of athermoplastic resin material or others that are adhesive such aspolyimide. In a process of removing the second substrate 10 b that willbe described later, such materials may cause ablation when they areheated and evaporated by irradiation of laser light with a predeterminedwavelength, and by the action of ablation, the first and second resinfilms 311 a and 313 a may easily lose their adhesion properties. Such athermoplastic resin material is not the only option, and any materialmay be used as long as it absorbs laser light with a predeterminedwavelength, and causes ablation.

On the second resin film 313 a of the temporary attachment layer 31 a,the second substrate 10 b is affixed as shown in FIG. 11A. The secondsubstrate 10 b is a disk-shaped semiconductor wafer made of sapphire(Al₂O₃), for example.

The temporary attachment layer 31 a is not restricted to the abovestructure, and may include only the first resin film 311 a and thebonding layer 312 a, for example. Alternatively in the above process,the temporary attachment layer 31 a may be entirely or partially formedin advance on the second substrate 10 b for attaching together theinorganic film 40 a and the second substrate 10 b.

Next, as shown in FIG. 11B, the first substrate 10 a is removed toexpose a second plane 202 a of the light-emitting layer 20 a on theopposite side of the first plane 201 a (ST106). In this process, thefirst substrate 10 a is removed first by wet etching, for example. Atthis time, used is an etchant showing a high etching selection ratiobetween the stop layer 214 a and the first substrate 10 a. This thuscontrols the progress of the above-mentioned wet etching in the stoplayer 214 a so that the first substrate 10 a is removed without fail.The stop layer 214 a is then removed by dry etching, for example. As aresult, the first contact layer 211 a is exposed on the light-emittinglayer 20 a.

In this process, the second plane 202 a is the surface of the firstcontact layer 211 a. The layer structure from the first contact layer211 a to the second cladding layer 221 a (the second contact layer) isreferred to as light-emitting layer 20 b.

Next, as shown in FIG. 12A, the second plane 202 a is formed thereonwith a second electrode 720 a (ST107). This second electrode 720 a ispatterned in the circular shape with the diameter of about 1 to 20 μm,for example. The second electrode 720 a is formed at least one to eachof the element regions 1 a.

Also in this embodiment, the second electrode 720 a is used as a mask toetch the first contact layer 211 a. This removes the first contact layer211 a except for the region directly below the second electrode 720 a asshown in FIG. 12A. The first contact layer after the patterning isdenoted as first contact layer 211 b. Moreover, after this process, thesecond plane is the surface of the second electrode 720 a and that ofthe second cladding layer 212 a, and is denoted as second plane 202 b.

Next, as shown in FIG. 12B, the inorganic film 40 a is used as anetching stop layer to etch the light-emitting layer 20 a from the secondplane 202 b, thereby forming a first separation groove 61 a (ST108). Bythis first separation groove 61 a, the light-emitting layer 20 a isseparated for each of the elements (element regions) la. In thisprocess, the light-emitting layer 20 a is etched by dry etching, forexample.

First of all, a mask layer M1 is formed to each of the element regions 1a on the second plane 202 b. This mask layer M1 is patterned for each ofthe element regions 1 a to conform to the shape of the second plane 202after the formation of the elements 1. That is, the mask layer M1includes an aperture M11, which is formed along the boundary between theelement regions 1 a. The mask layer M1 may be made of a material with alow etching rate in the etchant used in this process, and may be SiO₂,SiN, Ti, Ni, Cr (chromium), Al, or others.

Next, the first separation groove 61 a is formed along the boundarybetween the element regions 1 a by dry etching via the aperture M11 ofthe mask layer M1. At this time, used is an etching gas (etchant)showing a high etching selection ratio between a semiconductor materialof AlGaInP, GaAs, or GaP used to form the light-emitting layer 20 a, anda material of SiN, or SiO₂ used to form the inorganic film 40 a, forexample. Such an etchant is exemplified by SiCl₄ (silicon tetrahalide).With such an etchant, even if an etching rate is not uniform in theplane of the first substrate 10 a, the first separation groove 61 a mayhave a uniform depth in the plane by the inorganic film 40 a serving asan etching stop layer. In the below, an etching gas for use with dryetching is also referred to as etchant.

Also in this process (ST108), the cross-sectional area of thelight-emitting layer 20 a for each of the element 1 a may be graduallyincreased from the second plane 202 b toward the first plane 201 a. Thatis, in the first separation groove 61 a, the cross-sectional area of abottom plane 612 a is smaller than that of the aperture portion on theside of the second plane 202 b. Such a first separation groove 61 a maybe formed as appropriate under conditions for taper etching. Thespecific conditions for etching are dependent on the wafer size, thestructure of an etching apparatus, or others, e.g., the antenna power of100 to 1000 W, the bias power of 10 to 100 W, the processing pressure of0.25 to 1 Pa, and the substrate temperature of 100 to 200° C. Herein,the expression of “cross-sectional area” denotes the area of across-section in the direction orthogonal to the Z-axis direction. Afterthe first separation groove 61 a is formed as above, the mask layer M1is removed by etching, for example.

In this process (ST108), the first separation groove 61 a is formed witha wall plane 611 a being tapered, and the bottom plane 612 a. From thewall plane 611 a, the end planes of the layers in the light-emittinglayer 20 b are exposed except for the first contact layer 211 b, andfrom the bottom plane 612 a, the inorganic film 40 a is exposed. Thewall plane 611 a corresponds to the circumferential plane 203 of thelight-emitting element 1.

Next, as shown in FIG. 13A, an optical function film 50 a is formed tocover the wall plane 611 a and the bottom plane 612 a of the firstseparation groove 61 a, and the second plane 202 b (ST109). As describedabove, the optical function film 50 a is in the layer structureincluding a first insulation layer 51 a, a reflection layer 53 a, and asecond insulation layer 52 a. These layers are formed in order.

FIGS. 16A to 17B are each a schematic cross-sectional view forillustrating this process (ST109). FIGS. 16A to 17B do not show thefirst and second concave-convex structures 210 a and 410 a, the layersin the temporary attachment layer 31 a, and the second substrate 10 b.

First of all, as shown in FIG. 16A, the first insulation layer 51 a isformed on the wall and bottom planes 611 a and 612 a in the firstseparation groove 61 a, and on the second plane 202 b (ST109-1). Forforming the first insulation layer 51 a, used in this process is CVD(Chemical Vapor Deposition) or sputtering, for example. The firstinsulation layer 51 a may be also in the layer structure.

Next, the first insulation layer 51 a is formed thereon with thereflection layer 53 a (ST109-2). For pattering the reflection layer 53 ain this process, lifting-off is applicable, for example. That is, asshown in FIG. 16B, a resist R1 is formed on a region where thereflection layer 53 a is not expected to be formed. The resist R1 may bea positive resist, or a negative resist. Using a positive resist mayprevent halation during exposure to light. The region where the resistR1 is formed includes, specifically, the region including the secondelectrode 720 a when it is viewed from the Z-axis direction, and theregion substantially at the center on the bottom plane 612 a. Theseregions respectively correspond to the aperture portion 534 of thereflection layer 53 and the separation groove portion 60 when theelement 1 is completed.

To be specific, a metallic layer 53 b made of a metal or others isformed entirely over the first insulation layer 51 a including theresist R1 as appropriate by sputtering, vapor deposition, ion plating,or plating, for example. As an example, this metallic layer 53 b is asappropriate in the layer structure including Al and Au, for example.With such a metallic layer 53 b, light with a wavelength of about 500 to700 nm may be reflected with high reflectivity. Moreover, usingsputtering may improve the adhesion between the metallic layer 53 b andthe first insulation layer 51 a.

The resist R1 with the metallic layer 53 b is then removed. As shown inFIG. 17A, this obtains the reflection layer 53 a including first andsecond aperture portions 531 a and 532 a, which correspond to theaperture portion 534.

Thereafter, as shown in FIG. 17B, the reflection layer 53 a is formedthereon with the second insulation layer 52 a (ST109-3). In thisprocess, the reflection layer 53 a and the first insulation layer 51 aare entirely covered thereon by the second insulation layer 52 a.Similarly to the first insulation layer 51 a, the second insulationlayer 52 a may be formed as appropriate by CVD, sputtering, or coating,for example.

In the above-mentioned manner, the optical function film 50 a is formedentirely on the inner surface of the second plane 202 b and that of thefirst separation groove 61 a.

In the next process, as shown in FIG. 13B, the optical function film 50a is partially removed to expose the second electrode 720 a (ST110).This forms a connection hole 540 a to the first and second insulationlayers 51 a and 52 a of the optical function film 50 a. This process isfirst performed by etching or others via a resist (not shown), which ispatterned in the shape conforming to the second electrode 720 a.

Thereafter, as shown in FIG. 14A, the second plane 202 b is formedthereon with an external connection terminal 730 a for electricalconnection with each of the second electrodes 720 a (ST111).Alternatively, to form this external connection terminal 730 a in thisprocess, a metallic film may be formed on the second plane 202 b bysputtering, vapor deposition, ion plating, plating, or others asappropriate, and the metallic film may be patterned in a predeterminedshape by wet etching, dry etching, or others. Still alternatively, toform the external connection terminal 730 a, by lifting-off, a metallicfilm may be formed after a resist is formed in a predetermined pattern.As such, the external connection terminal 730 a is formed on the secondelectrode 720 a in the connection hole 540 a, and on the opticalfunction film 50 a on the second plane 202 b.

This also forms a space between the adjacent external connectionterminals 730 a on the first groove portion 61 a. In the below, thefirst groove portion 61 a including the space is referred to as grooveportion 613 a.

Next, on the external connection terminal 730 a, a third substrate 10 cis attached via the attachment layer 30 a to be freely separatedtherefrom (ST112).

As shown in FIG. 14B, first of all in this process, the groove portion613 a is filled with a resin R2. This accordingly prevents formation ofa void resulted from the groove portion 613 a when the third substrate10 c is attached. The manner of filling the resin R2 is not particularlyrestrictive, and may be coating, spin coating, spraying, dipping, orothers as appropriate. The resin R2 may be filled to be substantiallylevel with the surface of the external connection terminal 730 a byetching-back after coating. The material of the resin R2 is notparticularly restrictive.

Next, as exemplarily shown in FIG. 15A, an adhesive resin R3 is formedon the resin R2 and the external connection terminal 730 a. Thisaccordingly improves the adhesion between the attachment layer 30 a andthe external connection terminal 730 a. This resin R3 corresponds to theresin film 732 described above. The manner of forming the resin R3 isnot particularly restrictive, and may be coating, spin coating,spraying, dipping, or others as appropriate. FIG. 15A shows the inverted(upside-down) structure of FIG. 14B.

Thereafter, on the external connection terminal 730 a and the resin R3,the third substrate 10 c including the attachment layer 30 a isattached. The third substrate 10 c corresponds to the above-mentionedsupport substrate 10, and is a disk-shaped semiconductor wafer made ofsapphire, for example.

The attachment layer 30 a may be formed on the third substrate 10 c bycoating, spin coating, spraying, dipping, or others as appropriate. Theattachment layer 30 a may be made of a thermoplastic resin material orothers that are adhesive such as polyimide, i.e., a material absorbinglaser light with a predetermined wavelength, and causing ablationsimilarly to the material used for the second resin film 313 a.

The manner of attaching the third substrate 10 c is not restricted tothe above. Alternatively, at least either the resin R2 or R3 may not beformed. Still alternatively, the attachment layer 30 a may not be alwaysformed on the third substrate 10 c, and may be formed on the externalconnection terminal 730 a (resins R2 and R3).

Next, by referring to FIGS. 15A and 15B, the second substrate 10 b isremoved to expose the inorganic film 40 a (ST113). The second substrate10 b is removed by the action of ablation, which occurs when the secondresin film 313 a is heated and evaporated by irradiation of laser lightwith a predetermined wavelength onto the second substrate 10 b, forexample. The second substrate 10 b is thus peeled off from the interfacewith the second resin film 313 a as shown in FIG. 15A. With such atechnique of laser ablation, the second substrate 10 b is easilyremoved.

Thereafter, other films and layers are removed by wet etching, dryetching, or others, i.e., the second resin film 313 a, the bonding layer312 a, and the first resin film 311 a. As a result, the temporaryattachment layer 31 a is removed in its entirety so that the inorganicfilm 40 a is exposed as shown in FIG. 15B.

After the inorganic film 40 a is exposed as above, the inorganic film 40a on the first electrode 710 a is removed, and a connection hole 420 ais formed. To form the connection hole 420 a, similarly to theconnection hole 540 a, this process is performed by dry etching orothers via a resist (not shown), which is patterned in the shapeconforming to the first electrode 710 a.

Also in FIG. 15B, the inorganic film 40 a remained on the bottom plane612 a of the first separation groove 61 a is etched to form a secondseparation groove 62 a (ST114). By this second separation groove 62 a,the inorganic film 40 a is separated for each of the elements 1 a. Inthis process, the second separation groove 62 a is formed by dry etchingsuch as RIE (Reactive Ion Etching), wet etching, or others.

In this process, first of all, a mask (not shown in FIG. 15B) is formedon the inorganic film 40 a for use to separate the elements 1. Using themask formed as above, the inorganic film 40 a is etched in the regionopposing to the bottom plane 612 a of the first separation groove 61 a.Next, the region of the optical function film 50 a formed to the bottomplane 612 a is similarly etched. The resins R2 and R3 and the attachmentlayer 30 formed to the region opposing to the bottom surface 612 a arealso isotropically etched. This forms the second separation groove 62 awith a depth reaching the third substrate 10 c from the inorganic film40 a. This second separation groove 62 a corresponds to the separationgroove portion 60 in the light-emitting element 1. Note that suchetching on the structure elements may be continuously performed underthe same conditions or different conditions.

In this embodiment, the reflection layer 53 a includes the secondaperture portion 532 a in the region opposite to the bottom plane 612 a,i.e., the region of the optical function film 50 a. Such a regionincludes only the first and second insulation layers 51 a and 52 a sothat the above-mentioned region of the optical function film 50 a isetched with ease. As to the resin R3 and the attachment layer 30 a, bybeing etched using the external connection terminal 730 a as a mask,only the resin R3 and the attachment layer 30 a may be left untouched inthe region opposite to the external connection terminal 730 a.

By this process, the above-mentioned light-emitting-element wafer 100 isformed by the structure elements being separated for each of theelements 1, i.e., the attachment layer 30 on the third substrate 10 c(the support substrate 10), the external connection terminal 730, thelight-emitting layer 20 and the inorganic film 40 covered by the opticalfunction film.

In the light-emitting element 1 in this embodiment, the first plane 201a of the light-emitting layer 20 a is formed thereon with the inorganicfilm 40 a, and the second plane 202 b on the opposite side is providedthereon with the optical function film 50 a, the external connectionterminal 730 a, and the attachment layer 30 a. That is, with the layerstructure in which the layers are stacked on the light-emitting layer 20a being the result of crystal growth to have the uniform in-planethickness, the elements 1 in the plane of the wafer may be formed withthe uniform thickness.

Further, in the process of forming the first separation groove 61 a bydry etching or others, the first separation groove 61 a is formed withthe uniform depth in the plane because the inorganic film 40 a serves asan etching stop layer. In other words, from the bottom plane 612 a ofthe first separation groove 61 a, the inorganic film 40 a is exposed.This thus obtains the structure in which, after the element 1 is formed,the inorganic film 40 and the optical function film are connectedtogether, and the second end portion 510 of the optical function filmand the first end portion 41 of the inorganic film 40 are stacked one onthe other. Such a structure thus leads to the light-emitting elements 1being all uniform in shape, and among the elements 1 on thelight-emitting-element wafer 100, their height difference from thesurface 11 may remain 10% or less, for example.

Still further, because the light-emitting layer 20 a is not expected toinclude the etching stop layer for forming the first separation groove61 a, the light-emitting layer 20 a is formed with a wider choice ofmaterials, and the manufacturing process is accordingly simplified.

Also by forming the first separation groove 61 a by dry etching, even ifthe area of the wafer is increased, and even if the first separationgroove 61 a is small and narrow, the shape thereof is more uniform inthe plane of the wafer.

In this embodiment, the reflection layer 53 a is formed by lifting-off.This achieves easy micromachining even if the reflection layer 53 a ismade of a chemically-stable metal. This also controls the effect of sideetching with a resist, and even if the size of the wafer is increased,the resulting reflection layer 53 a remains uniform in shape in theplane of the wafer.

FIG. 18A is a graph showing the relationship between the width of thefirst separation groove 61 a and the width of the second apertureportion 532 a (refer to FIGS. 17A and 17B) formed to the reflectionlayer 53 a between the elements 1 a adjacent to each other. FIG. 18Ashows a comparison between the cases of forming the reflection layer 53a by lifting-off and wet etching. Herein, the terms of “width” means thelength of the first separation groove 61 a or that of the secondaperture portion 532 a in the short-side direction.

Also in FIG. 18A, when the first separation groove 61 a has a relativelylarge width, the width of the second aperture portion 532 a does notdiffer largely depending on whether the reflection layer 53 a is formedby lifting-off or wet etching. On the other hand, as the firstseparation groove 61 a is reduced in width, the width of the secondaperture portion 532 a starts to differ largely depending on whether thereflection layer 53 a is formed by lifting-off or wet etching. To bespecific, with lifting-off, the width of the second aperture section 532a is reduced almost in proportion to the width of the first separationgroove 61 a.

With wet etching, the width of the second aperture portion 532 a remainsalmost the same even if the width of the first separation groove 61 a isreduced.

As such, forming the reflection layer 53 a by lifting-off ensures thegood accuracy for the width of the second aperture portion 532 a even ifthe light-emitting-element wafer 100 is reduced in size in its entirety.

Also with lifting-off, the resulting reflection layer 53 a may beuniform in shape in the plane of the light-emitting-element wafer 100 aswill be described later.

FIG. 18B is a graph showing a degree of misalignment of the reflectionlayer 53 a with respect to the width of the first separation groove 61 ain the plane of the light-emitting-element wafer 100. Similarly to FIG.18A, FIG. 18B shows a comparison between the cases of forming thereflection layer 53 a by lifting-off and wet etching. Herein, elementseparation masks for use in these cases are in the same shape.

As shown in FIG. 18B, with wet etching, the reflection layer 53 a showsa high degree of misalignment with respect to the width of the firstseparation groove 61 a as is away from the center of thelight-emitting-element wafer 100. On the other hand, with lifting-off,the reflection layer 53 a shows a low degree of misalignment withrespect to the width of the first separation groove 61 a irrespective ofits position in the light-emitting-element wafer 100.

The result of FIG. 18B confirms that forming the reflection layer 53 aby lifting-off leads to a low degree of misalignment thereof withrespect to the width of the first separation groove 61 a in the plane ofthe light-emitting-element wafer 100. Herein, the degree of misalignmentmeans a degree of positional displacement of the reflection layer 53 abecause the width of the first separation groove 61 a is formed in thesame manner in these two cases by lifting-off and wet etching. That is,the reflection layer 53 a formed by lifting-off is proved to be uniformin shape in the plane of the light-emitting-element wafer 100.

The light-emitting elements 1 on the light-emitting-element wafer 100formed as above are mounted on a display apparatus (electronicapparatus) 80, for example.

FIG. 19 is a schematic plan view of the display apparatus 80. To bespecific, the light-emitting element emitting red light (firstsemiconductor light-emitting element) 1 configures alight-emitting-element unit 81 together with a light-emitting elementemitting blue light (second semiconductor light-emitting element) 2, anda light-emitting element emitting green light (third semiconductorlight-emitting element) 3. Such a light-emitting-element unit 81 andothers are mounted in an arrangement on a substrate 810 of the displayapparatus 80 as a light-emitting-element module. Described next is amanufacturing method for the display apparatus 80 together with anexemplary structure thereof. Note that the elements 1, 2, and 3 of FIG.19 do not show coating resins, wiring, and others.

[Manufacturing Method for Display Apparatus]

FIG. 20 is a flowchart of a manufacturing method for the displayapparatus 80 in this embodiment, FIG. 21 is a schematic plan view forillustrating the manufacturing method, and FIGS. 22A to 22C are each aschematic cross-sectional diagram for illustrating the manufacturingmethod.

In FIG. 20, steps are numbered successively from step ST114 of FIG. 9.The number of elements 1 in FIG. 21 is only 12 for description.

By referring to FIG. 21, described is the outline of the manufacturingmethod for the display apparatus 80. First of all, the light-emittingelements 1 on the light-emitting-element wafer 100 are transferred ontoa first transfer substrate (transfer substrate) 910, and are arranged ata predetermined spacing larger than the width of the separation groovesection 60. The elements 1 are then transferred onto a second transfersubstrate 920, and are each covered by a covering layer 922, therebyforming a wiring pattern or others (not shown). Thereafter, the elements1 are transferred onto the substrate 810 of the electronic apparatus 80as light-emitting-element chips covered by the covering layer 922.

First of all, as shown in FIG. 22A, the first transfer substrate 910 ismade ready, which is disposed to oppose the inorganic film 40 of each ofthe elements 1 on the light-emitting-element wafer 100 (ST115). Thisfirst transfer substrate 910 is of a size that allows the elements 1 tobe arranged at a predetermined spacing therebetween. The first transfersubstrate 910 is a glass substrate or a plastic substrate, for example.

The transfer substrate 910 is formed thereon with a first temporaryattachment layer 911, and a bonding layer 912. The first temporaryattachment layer 911 is formed on the transfer substrate 910, and ismade of a fluorine resin, a silicone resin, a water-soluble adhesivesuch as PVA (polyvinyl alcohol), polyimide, or others. The bonding layer912 is formed on the first temporary attachment layer 911, and may bemade of an ultraviolet (UV) curing resin, a thermosetting resin, athermoplastic resin, or others.

The bonding layer 912 may include an uncured region 912 a, and a curedregion 912 b. In this structure, if the transferring light-emittingelements 1 are positioned to face the uncured region 912 a, thelight-emitting elements 1 may be transferred to the bonding layer 912without fail in the later transfer process. When the bonding layer 912is made of an UV curing resin, for example, the cured region 912 b maybe formed by selective UV irradiation only on a corresponding region forcuring. Alternatively, the uncured region 912 a may be formed with aconcave portion in the shape conforming to the light-emitting element 1.

Next, by referring to FIGS. 22A and 22B, the external connectionterminal 730 and the support substrate 10 are separated from each otherby laser ablation onto the attachment layer 30 from the side of thesupport substrate (third substrate) 10 of the light-emitting-elementwafer 100, thereby moving the elements 1 onto the first transfersubstrate (transfer substrate) 910 (ST116).

In this process, as shown in FIG. 22A, laser light Lb is directed towardthe attachment layer 30 of the light-emitting element 1 to be moved fromthe side of the support substrate 10. The laser is exemplified byExcimer laser with a predetermined emission wavelength, or harmonic YAG(yttrium aluminum garnet) laser. With such laser irradiation, theattachment layer 30 loses its adhesion properties as is heated andcured, and the resin therein is partially vaporized, whereby theattachment layer 30 and the external connection terminal 730 areexplosively peeled away from each other. That is, the element 1 isemitted in its entirety toward the Z-axis direction, and is bonded withthe bonding layer 912. In this manner, as shown in FIG. 22B, thelight-emitting element 1 is moved onto the bonding layer 912 on theopposite side.

The uncured region 912 a onto which the light-emitting element 1 ismoved is then exposed to UV irradiation or others to cure the uncuredregion 912 a. This secures the attachment of the light-emitting element1 to the bonding layer 912. Alternatively, the external connectionterminal 730 may be formed thereon with a wiring layer 740 asappropriate.

This process also forms a light-emitting-element wafer 200 including thefirst transfer substrate (support substrate) 910, and a plurality oflight-emitting elements 1. That is, by performing the above-mentionedprocesses on each desired element 1, obtained is thelight-emitting-element wafer 200 with a plurality of elements 1 arrangedon the first transfer substrate 910.

Next, in FIG. 22C, the light-emitting elements 1 are each moved onto thesecond transfer substrate 920, and removes the first transfer substrate910 (ST117). This second transfer substrate 920 is typicallysubstantially in the same size as the first transfer substrate 910, andis formed with a second temporary attachment layer 921 made of afluorine resin, a silicone resin, a water-soluble adhesive such as PVA,polyimide, or others. First of all, the external connection terminal 730and the wiring layer 740 of each of the elements 1 on the first transfersubstrate 910 are attached onto the second temporary attachment layer921. Next, laser light is directed from above the first transfersubstrate 910 toward the first temporary attachment layer 911 thereof,and the first temporary attachment layer 911 and the bonding layer 912are separated from each other. As a result, the bonding layer 912including the element 1 therein is moved onto the second temporaryattachment layer 921.

Alternatively, as shown in FIG. 22C, a third separation groove 63 may beformed to the bonding layer 912 between the adjacent elements 1 toseparate the bonding layer 912 for each of the elements 1. If this isthe case, formed is a covering layer 922 being the bonding layer 912covering the element 1. Still alternatively, a wiring layer 750 may beformed for connection with the first electrode. In the below, thestructure of including the element 1 and the covering layer 922 thereforis referred to as light-emitting-element chip 90 for description. Thislight-emitting-element chip 90 includes the element 1, the coveringlayer 922, and the wiring layers 740 and 750.

The light-emitting-element chip 90 and others are each moved onto thesubstrate 810 of the display apparatus 80 (ST118). For suchtransferring, adopting the above-mentioned laser ablation is apossibility, or an absorption retainer may be used for mechanicaltransferring. The substrate 810 is configured as a wiring board formedwith a predetermined driving circuit that is not shown.

As shown in FIG. 21, the light-emitting-element chips are arranged onthe substrate 810 at a predetermined pitch along the X- and Y-axisdirections. The predetermined pitch is three times the length of thelight-emitting-element chip 90 along the X- and Y-axis directions. Withsuch an arrangement, a light-emitting-element module 81 is formed byplacing two other light-emitting-element chips between thelight-emitting-element chips 90 each including the light-emittingelement that emits red light. One of the two otherlight-emitting-element chips includes the light-emitting element 2 thatemits blue light, and the other includes the light-emitting element 3that emits green light. With a spacing between thelight-emitting-element chips as above, the spacing is utilized to form awiring pattern or others.

In the above manner, the display apparatus 80 of FIG. 19 ismanufactured. That is, the display apparatus 80 includes the substrate810 formed with a driving circuit, the semiconductor light-emittingelements 1 that emit red light, the semiconductor light-emittingelements 2 that emit blue light, and the semiconductor light-emittingelements 3 that emits green light. These semiconductor light-emittingelements 1, 2, and 3 are arranged on the substrate 810.

In addition to the above-mentioned processes, another transfer substratemay be used for transferring. That is, after the process of moving theelements 1 onto the second transfer substrate 920, additional processesmay be performed to move the elements 1 onto third and fourth transfersubstrates, for example. This increases the spacing between the elements1 for moving, and is advantageous to form a wiring layer or tomanufacture a large-sized display apparatus, for example.

Assuming that an element separation mask is largely misaligned, andthere is a displacement of center of gravity between the attachmentlayer and the light-emitting layer, the following problems are caused inthe process of moving the elements 1 onto the first transfer substrate910 by laser ablation (ST116).

FIGS. 23A to 23C are each a schematic diagram showing how a transferprocess onto a transfer substrate is performed when there is adisplacement of center of gravity between an attachment layer and alight-emitting layer, and specifically, showing how a process isperformed to move an element 1E onto a first transfer substrate 910Efrom a support substrate 10E (ST116). The expression of “displacement”denotes a displacement on the XY plane. In the drawings, alternate longand short dashed lines denote the center of gravity of the attachmentlayer 30E, and that of an element separation mask ME. The elementseparation mask ME is actually removed, but is indicated by chaindouble-dashed lines for description.

As exemplarily shown in FIG. 23A, when the element separation mask ME ismisaligned to the right with the center of gravity of a light-emittinglayer 20E, it means that the center of gravity of the attachment layer30E is also displaced to the right from that of the light-emitting layer20E as is etched via the element separation mask ME. If laser light Lbis directed toward the resulting attachment layer 30E of thelight-emitting element 1E, a clockwise rotating moment is produced tothe element 1E at the time of ablation (FIG. 23B). This causes theelement 1E to be bonded on the right-side surface to a bonding layer912E of the first transfer substrate 910E (FIG. 23C).

The inventor and others actually confirm that when there is apredetermined amount or more of the center-of-gravity displacementbetween the attachment layer 30E and the light-emitting layer 20E, theelement 1 attaches on the side surface to the bonding layer 912E asshown in FIG. 23C.

Even if such a displacement is less than the predetermined amount, it isconfirmed that the transfer position is also displaced by the element 1Ebeing emitted obliquely in the Z-axis direction at the time of ablation,for example.

In this embodiment, as described by referring to FIG. 18B, the elementseparation mask is prevented from being misaligned in the plane of thelight-emitting-element wafer.

This also prevents a displacement of center of gravity between theattachment layer and the light-emitting layer so that, as shown in FIG.23C, the element is prevented from rotating at the time of transferring,or the transfer position is prevented from being displaced. Also as willbe described later, in this embodiment, even if the element separationmask is misaligned, the transfer position may be prevented from beingdisplaced.

FIG. 24 is a graph showing the relationship between a degree ofmisalignment of the element separation mask and a displacement degree ofthe transfer position, and more specifically, showing results of acomparison between the reflection layer 53 whose end surface 532 s isexposed (example of experiment 1) and the reflection layer 53 whose endsurface 532 s is not exposed (example of experiment 2). Herein, thedisplacement of the transfer position denotes the degree of displacementfrom the intended transfer position along the short side of the firstplane 201 (or the second plane 202).

FIG. 24 shows that, in the example of experiment 2, a degree ofdisplacement of the transfer position is increased in proportion to adegree of misalignment of the element separation mask (indicated by asolid line). On the other hand, in the example of experiment 1, even ifa degree of misalignment of the element separation mask is increased,the transfer position is not displaced to the extent as in the exampleof experiment 1 (indicated by a broken line).

The results in FIG. 24 confirm that, with the light-emitting element 1in which the end surface 532 s of the reflection layer 53 is exposed,even if the element separation mask is misaligned, the transfer positionis not displaced thereby. This is because, in the process of forming thesecond separation groove 62 a, a mask used therefor is the reflectionlayer 53 in the substantially uniform shape. That is, in thisembodiment, because the reflection layer 53 is highly controlled inshape, even if misalignment occurs to the element separation mask, thismay not result in a displacement of the transfer position or problemsduring transferring.

Also in this embodiment, the second region 532 of the reflection layer53 protrudes in a direction parallel to the first plane 201, and is notexposed from the inorganic film 40. That is, when the wiring layer 750is pulled from the first electrode 710 to be above the inorganic film40, two insulation layers are sandwiched between the reflection layer 53and the wiring layer 750, i.e., the inorganic film 40, and the firstinsulation layer 51. This accordingly controls a short circuit betweenthe reflection layer 53 and the wiring layer 750, and prevents problemsto be caused to the elements 1.

Second Embodiment

FIG. 25 is a cross-sectional view of a main part of alight-emitting-element wafer according to a second embodiment of thepresent disclosure, showing the structure thereof. In the drawing, anystructure element corresponding to that in the first embodiment isprovided with the same reference numeral, and is not described in detailagain.

Compared with the first embodiment, in a light-emitting element 1A for alight-emitting-element wafer 100A in this embodiment, a second region532A of a reflection layer 53A protrudes in a direction parallel to acircumferential plane 203A.

Similarly to the first embodiment, a light-emitting layer 20A is asemiconductor, including a first plane 201A that includes a firstelectrode 710A, a second plane 202A is opposing to the first plane 201Aand includes a second electrode 720A, and a circumferential plane 203Athat connects together the first and second planes 201A and 202A.

The light-emitting layer 20A emits red light and includes GaAs andAlGaInP semiconductor compounds, but this is not restrictive.

Also similarly to the first embodiment, the light-emitting layer 20Aincludes a first semiconductor layer 21A of a first conductivity type,an active layer 23A formed on the first semiconductor layer 21A, and asecond semiconductor layer 22A of a second conductivity type formed onthe active layer 23A. In this embodiment, the first conductivity type isassumed to be p, and the second conductivity type is assumed to be n,but this is not restrictive.

Also similarly to the first embodiment, in the light-emitting layer 20A,the first plane 201A may be formed to be larger than the second plane202A like a square frustum.

Also similarly to the first embodiment, the first plane 201A may includea first concave-convex structure 210A that may be changed as appropriateso as to provide emitted light with desired optical characteristics.

In this embodiment, the light-emitting element 1A may or may not includean inorganic film as shown in FIG. 25.

An optical function film 50A protrudes as a whole upward in the Z-axisdirection to be higher than a reference plane 201As of the first plane201A along the circumferential plane 203A. In the second plane 202A, theoptical function film 50A is formed to cover a reflection region (notshown in FIG. 25). The optical function film 50A also covers thecircumferential plane 203A in its entirety, and protrudes upward in theZ-axis direction along the circumferential plane 203A.

Similarly to the first embodiment, the optical function film 50Aincludes a reflection layer 53A, a first insulation layer 51A, and asecond insulation layer 52A. The reflection layer 53A is able to reflectlight coming from the light-emitting layer 20A. The first insulationlayer 51 is formed between the light-emitting layer 20A and thereflection layer 53A, and the second insulation layer 52A is formed onthe reflection layer 53A.

The reflection layer 53A includes first and second regions 531A and532A. The first region 531A covers the second plane 202A and thecircumferential plane 203A, and the second region 532A protrudes fromthe first region 531A toward the outside of the light-emitting layer20A. In this embodiment, the first region 531A of the reflection layer53A is a region covering the second plane 202A and the circumferentialplane 203A, and opposing to each of the second plane 202A and thecircumferential planes 203A. The second region 532A of the reflectionlayer 53A is a region protruding upward in the Z-axis direction from thefirst region 531A toward the light-emitting layer 20A. To be morespecific, the second region 532A is a region being higher than thereference plane 201As of the first plane 201A in the Z-axis direction.

That is, in this embodiment, an end plane 532As of the reflection layer53A is formed to be higher than the height of the first plane 201A. The“height” herein denotes the height of the structure from a surface 11Aof a support substrate 10A along the Z-axis direction, and theexpression of “the height of the first plane 201A” denotes the height ofthe reference plane 201As of the first plane 201A.

With the reflection layer 53A having the second region 532A, lightdirected to the circumferential edge of the first plane 201A isreflected by the second region 532A, and then is directed toward thefront of the light-emitting element 1A (upward in the Z-axis direction).This accordingly further enhances the emission intensity toward thefront of the light-emitting element 1A.

Also similarly to the first embodiment, in the second region 532A, theend plane 532As is exposed so that the heat dissipation of thelight-emitting element 1A may be improved.

FIGS. 26A to 30B are each a schematic cross-sectional view of thelight-emitting-element wafer 100A, showing a manufacturing methodtherefor. Described mainly below are only differences from themanufacturing method for the light-emitting-element wafer 100 in thefirst embodiment (refer to FIGS. 10A to 15B).

First of all, as shown in FIG. 26A, a light-emitting layer 20Aa isformed on a first substrate 10Aa. Herein, on the first substrate 10Aamade of gallium arsenide (GaAs), layers are each formed as appropriateby Metal Organic Chemical Vapor Deposition (MOCVD), for example.

The layers are formed in order on the first substrate 10Aa by crystalgrowth, i.e., a second-conductive-type stop layer 224Aa, a secondcontact layer 221Aa, and a second cladding layer 222Aa. The stop layer224Aa functions as an etching stop layer when the first substrate 10Aais removed similarly to the stop layer 214 a in the first embodiment.Among the above layers, because the stop layer 224Aa is removed in thelater process together with the first substrate 10Aa, the second contactlayer 221 aA and the second cladding layer 222Aa are included in asecond semiconductor layer 22A of the light-emitting element 1A.

Thereafter, formed is a multiquantum well layer 23Aa that serves as theactive layer 23A of the light-emitting element 1A, and on themultiquantum well layer 23Aa, layers are formed in order by crystalgrowth, i.e., a first-conductive-type first cladding layer 211Aa, and afirst contact layer. Note that the first contact layer is not shown inFIGS. 26A to 30B. The structure of the light-emitting layer 20Aa is notrestricted to the above, and may be changed as appropriate.

Also as shown in FIG. 26A, a connection region (not shown) of the secondplane 202Aa is formed with a second electrode 720Aa. This secondelectrode 720Aa is formed as appropriate by sputtering, vapordeposition, ion plating, plating, or others, and is patterned in apredetermined shape such as oval, for example. Such a second electrode720Aa is formed at least one to each element region 1Aa. After thisprocess, the second plane is the surface of the second electrode 720Aaand that of the second cladding layer 221Aa, and is referred to assecond plane 202Ab.

Next, as shown in FIG. 26B, the light-emitting layer 20Aa is etched fromthe second plane 202Ab to form a first separation groove 61Aa thatseparates the light-emitting layer 20Aa for each of the elements(element regions) 1Aa. In this process, as shown in FIG. 26B, a masklayer MA1 is first formed on the second plane 202Ab to conform to theshape of the second plane 202A after the formation of the elements 1Aa.The mask layer MA1 may be made of a material with a low etching rate inthe etchant used in this process, and may be SiO₂, SiN, Ti, Ni, Cr, Al,or others.

Next, by using the mask layer MA1 as a mask, the light-emitting layer20Aa is etched by wet etching or dry etching, for example. In thisprocess, by using an etchant showing a high etching selection ratiobetween the first substrate 10Aa and the light-emitting layer 20Aa, theresulting first separation groove 61Aa has a depth reaching the firstsubstrate 10Aa. Note that the depth of the first separation groove 61Aais not particularly restrictive as long as the stop layer 224Aa isexposed therefrom.

Also in this process, the cross-sectional area of the light-emittinglayer 20Aa for each of the elements 1Aa may be gradually increased fromthe second plane 202Ab toward a first plane 201Aa. That is, in the firstseparation groove 61Aa, the cross-sectional area of a bottom plane 612Aais smaller than that of the aperture portion on the side of the secondplane 202Ab. Such a first separation groove 61Aa may be formed asappropriate under conditions for taper etching similarly to the firstembodiment.

This forms the first separation groove 61Aa with a wall plane 611Aabeing tapered, and the bottom plane 612Aa.

The wall plane 611Aa corresponds to the circumferential plane 203A ofthe light-emitting element 1A, and from the bottom plane 612Aa, thefirst substrate 10Aa is exposed.

Next, by referring to FIGS. 26C to 27B, an optical function film 50Aa isformed to cover the wall plane 611Aa and the bottom plane 612Aa of thefirst separation groove 61Aa, and the second plane 202Ab.

First of all, as shown in FIG. 26C, a first insulation layer 51Aa isformed by CVD, sputtering, or others on the wall and bottom planes 611Aaand 612Aa in the first separation groove 51Aa, and on the second plane202Ab.

Next, as shown in FIG. 27A, the first insulation layer 51Aa is formedthereon with the reflection layer 53Aa. The reflection layer 53Aa inthis embodiment is so formed as to reach the bottom plane 612Aa. Forpatterning the reflection layer 53Aa in this process, similarly to thefirst embodiment, lifting-off is applicable but is not restrictive.

Thereafter, as shown in FIG. 27B, the reflection layer 53Aa is formedthereon with a second insulation layer 52Aa by CVD, sputtering, orothers. This forms the optical function film 50Aa entirely on the innersurface of the second plane 202Ab and that of the first separationgroove 61Aa.

Next, as shown in FIG. 27C, the optical function film 50Aa is partiallyremoved to expose the second electrode 720Aa. This forms a connectionhole 540Aa to the first and second insulation layers 51Aa and 52Aa ofthe optical function film 50Aa.

Next, as shown in FIG. 28A, the second plane 202Ab is formed thereonwith an external connection terminal 730Aa for electrical connectionwith each of the second electrodes 720Aa. To be specific, the externalconnection terminal 730Aa is formed on the second electrode 720Aa in theconnection hole 540Aa, and on the optical function film 50Aa on thesecond plane 202Ab.

This also forms a space between the adjacent external connectionterminals 730Aa on the first groove portion 61Aa.

In the below, the first groove portion 61Aa including the space isreferred to as groove portion (not shown).

Next, on the external connection terminal 730Aa, a second substrate 10Abis attached via an attachment layer 30Aa to be freely separatedtherefrom.

As shown in FIG. 28B, first of all in this process, a groove portion613Aa is filled with a resin RA2. The resin RA2 may be filled to besubstantially level with the surface of the external connection terminal730Aa by etching-back after coating. The material of the resin RA2 isnot particularly restrictive.

Next, as exemplarily shown in FIG. 29A, an adhesive resin RA3 is formedon the resin RA2 and the external connection terminal 730Aa. Thisaccordingly improves the adhesion between the attachment layer 30Aa andthe external connection terminal 730Aa. The adhesive resin RA3 may beformed up to the external connection terminal 730Aa (refer to FIGS. 15Aand 15B), and is not shown in FIGS. 29A to 30B.

FIG. 29A shows the inverted (upside-down) structure of FIG. 28B.

Also as shown in FIG. 29A, on the external connection terminal 730Aa andthe resin RA3, the second substrate 10Ab including the attachment layer30Aa is attached. The second substrate 10Ab corresponds to theabove-mentioned support substrate 10A, and is a disk-shapedsemiconductor wafer made of sapphire, for example. The attachment layer30Aa may be made of a thermoplastic resin material that is adhesive suchas polyimide similarly to the first embodiment, i.e., a materialabsorbing laser light with a predetermined wavelength, and causingablation.

The manner of attaching the second substrate 10Ac is not restricted tothe above. Alternatively, at least either the resin RA2 or RA3 may notbe formed.

Next, in FIG. 29B, the first substrate 10Aa is removed to expose thefirst plane 201Aa. In this process, the first substrate 10Aa is removedfirst by wet etching, for example.

At this time, used is an etchant showing a high etching selection ratiobetween the stop layer 224Aa and the first substrate 10Aa. This thuscontrols the progress of the above-mentioned wet etching in the stoplayer 224Aa so that the first substrate 10 a is removed without fail.The stop layer 224Aa is then removed by dry etching, for example. As aresult, the second contact layer 221Aa is exposed on the light-emittinglayer 20Aa.

The first plane 201Aa is formed thereon with the first electrode 710Aain a predetermined shape. In this embodiment, the first electrode 710Aais used as a mask to etch the second contact layer 221Aa. This removesthe second contact layer 221Aa except for the region directly below thefirst electrode 710Aa as shown in FIG. 29B. The second contact layerafter the patterning is denoted as second contact layer 221Ab. Moreover,after this process, the first plane is the surface of the firstelectrode 710Aa and that of the second cladding layer 222Aa, and isdenoted as first plane 201Ab.

Next, as shown in FIG. 30A, the first plane 201Aa is formed in a firstconcave-convex structure 210Aa. The first concave-convex structure 210Aais formed by photolithography, reactive ion etching (RIE), or others.Alternatively, the first plane 201Ab may be subjected to roughening byoxygen ion or blast processing, for example. For forming the firstconcave-convex structure 210Aa, a mask or others may or may not beformed.

Next, as shown in FIG. 30B, a second separation groove 62Aa is formed toseparate the optical function film 50Aa for each of the elements 1Aa.This process forms the second separation groove 62Aa by dry etching, wetetching, or others such as RIE. As to the attachment layer 30Aa, bybeing etched using the external connection terminal 730Aa as a mask,only the resin RA3 and the attachment layer 30Aa may be left untouchedin the region opposing to the external connection terminal 730Aa.

By this process, the above-mentioned light-emitting-element wafer 100Ais formed by the structure elements being separated for each of theelements 1A, i.e., the attachment layer 30A on the second substrate 10Ab(the support substrate 10A), the external connection terminal 730A, andthe light-emitting layer 20A covered by the optical function film 50A.

As described in the first embodiment above, the elements 1A are eachmounted onto an electronic apparatus such as display apparatus.

As above, by forming the reflection layer 53Aa to reach the bottom plane612Aa, the optical function film 50A is formed with ease in which theend plane 532As of the reflection layer 53A is exposed, and thereflection layer 53A covers the light-emitting layer 20A without fail.

With the manufacturing method for the light-emitting-element wafer 100Ain this embodiment, the light-emitting-element wafer 100A ismanufactured using two substrates, i.e., the first substrate 10Aa, andthe second substrate 10Ab serving as the support substrate 10A. Comparedwith the manufacturing method of the light-emitting-element wafer 100 inthe first embodiment, the manufacturing method in this embodiment iswith the reduced number of processes and the reduced manufacturing cost,thereby increasing the productivity to a further degree.

Third Embodiment

FIG. 31 is a cross-sectional view of a main part of alight-emitting-element wafer according to a third embodiment of thepresent disclosure, showing the structure thereof. In the drawing, anystructure element corresponding to that in the first and secondembodiments is provided with the same reference numeral, and is notdescribed in detail again.

Compared with the second embodiment, in a light-emitting element 1B fora light-emitting-element wafer 100B in this embodiment, a tilt anglebetween a reflection layer 53B and a circumferential plane 203B isdifferent.

Similarly to the first and second embodiments, a first region 531B ofthe reflection layer 53B includes a first reflection plane 5311Bopposing to a second plane 202B, and a second reflection plane 5312Bopposing to a circumferential plane 203B. In this embodiment, the secondreflection plane 5312B is so formed that a first tilt angle of thesecond reflection plane 5312B with the first plane 201B is smaller thana second tilt angle of the circumferential plane 203B with the firstplane 201B. Herein, the expression of “tilt angle with the first plane201B” denotes an angle with a reference plane 201Bs of the first plane201B.

Such a structure allows adjustment of an angle of emitted light to bereflected by the second reflection surface 5312B so that emitted lightis with improved orientation.

Also similarly to the second embodiment, the reflection layer 53B of thelight-emitting element 1B of FIG. 31 includes a second region 532B thatprotrudes in a direction parallel to the circumferential plane 203B.With this structure, light directed to the circumferential edge of thefirst plane 201B is reflected on the second region 532B, therebyenhancing the emission intensity toward the front of the light-emittingelement 1B.

The light-emitting-element wafer 100B in this embodiment is manufacturedas below.

FIGS. 32A to 33C are each a schematic cross-sectional view of thelight-emitting-element wafer 100B, showing a manufacturing methodtherefor. In the manufacturing method in this embodiment, processesexcept for a process of forming an optical function film are similar tothose in the manufacturing method in the second embodiment. Therefore,described mainly below are only differences from the second embodiment.

FIGS. 32A and 32B are diagrams showing processes similar to those inFIGS. 26A and 26B in the second embodiment. That is, as shown in FIG.32A, a first substrate 101Ba is first formed thereon with alight-emitting layer 20Ba. Also as shown in FIG. 32A, a connectionregion (not shown) of the second plane 202Ba is formed with a secondelectrode 720Ba.

Next, as shown in FIG. 32B, a light-emitting layer 20Ba is etched fromthe second plane 202Bb including the second electrode 720Ba to form afirst separation groove 61Ba that separates the light-emitting layer20Ba for each element (element region) 1Ba. Similarly to the secondembodiment, this process forms the first separation groove 61Ba with awall plane 611Ba being tapered, and a bottom plane 612Ba. The wall plane611Ba corresponds to the circumferential plane 203B of thelight-emitting element 1B, and from the bottom plane 612Ba, a firstsubstrate 10Ba is exposed.

In this process, the wall plane 611Ba is so formed that the angle withthe bottom plane 612Ba is about 60°, for example. This angle correspondsto the above-mentioned second tilt angle.

In this process, the bottom plane 612Ba is formed with a width WB. Byadjusting the width WB, as shown in FIG. 31, an end plane 532Bs isexposed from the second region 532B of the reflection layer 53B. Herein,the “width of the bottom plane” denotes the length of the bottom plane612Ba along the short-side direction.

Next, by referring to FIGS. 32C to 33B, an optical function film 50Ba isformed to cover the wall plane 611Ba and the bottom plane 612Ba of thefirst separation groove 61Ba, and the second plane 202Bb.

First of all, as shown in FIG. 32C, a first insulation layer 51Ba isformed on the wall plane 611Ba and the bottom plane 612Ba of the firstseparation groove 61Ba, and on the second plane 202Bb. The firstinsulation layer 51Ba is made of an inorganic material with flowproperties such as SOG (Spin-On Glass; film-forming SiO₂ coatingmaterial), and a light-resistant resin material including polyimideresin, polyester resin, epoxy resin, or others. Such a first insulationlayer 51Ba is formed by spin coating, coating, spraying, or others.Similarly to the first and second embodiments, the first insulationlayer 51Ba may be a laminate film including first and second films,i.e., first film made of silicon oxide such as SiO₂, SiN, TiN, TiO₂, orany other inorganic insulation materials, and the second film made fromany of the above-mentioned materials with flow properties.

As such, in this embodiment, the first insulation layer 51Ba is made ofa material with flow properties. This allows reduction of an angleformed by the surface of the first insulation layer 51Ba with the bottomplane 612Ba to be smaller than the above-mentioned second tilt angle.This angle corresponds to the above-mentioned first tilt angle. With thewall plane 611Ba being tapered, even if a material in use is with arelatively low viscosity, the first insulation layer 51Ba is formed withease.

Next, as shown in FIG. 33A, the first insulation layer 51Ba is formedthereon with a reflection layer 53Ba. The reflection layer 53Ba in thisembodiment is so formed as to reach the bottom plane 612Ba. Forpatterning the reflection layer 53Ba in this process, similarly to thefirst and second embodiments, lifting-off is applicable but is notrestrictive.

This process forms the reflection layer 53Ba on the surface of the firstinsulation layer 51Ba whose angle in the Z-axis direction is smallerthan the second tilt angle.

This accordingly reduces the angle between the reflection layer 53Ba andthe second plane 202Bb to be smaller than the above-mentioned secondtilt angle.

As shown in FIG. 33B, the reflection layer 53Ba is then formed thereonwith a second insulation layer 52Ba. The material for the secondinsulation layer 52Ba is not particularly restrictive, and may be madeof silicon oxide such as SiO₂, SiN, TiN, TiO₂, or any other inorganicinsulation materials similarly to the first embodiment, for example. Inthis case, the second insulation layer 52Ba may be formed by CVD,sputtering, or others depending on the selected material. Alternatively,similarly to the first insulation layer 51Ba in this embodiment, amaterial with flow properties may be used to form the second insulationlayer 52Ba. In this case, the second insulation layer 52Ba may be formedby spin coating, coating, spraying, or others.

The second insulation layer 52Ba may be a laminate film made from any ofsuch materials.

This forms the optical function film 50Ba entirely on the inner surfaceof the second plane 202Bb and that of the first separation groove 61Ba.

Next, processes similar to those in the second embodiment are performed.That is, the optical function film 50Ba is partially removed to exposethe second electrode 720Ba. The second plane 202Bb is formed thereonwith an external connection terminal 730Ba for electrical connectionwith each of the second electrodes 720Ba. The external connectionterminal 730Ba is attached thereon with a second substrate 10Bb via anattachment layer 30Ba to be freely separated therefrom. The firstsubstrate 10Ba is removed to expose the first plane 201Ba to form thefirst electrode 710Ba, and a first concave-convex structure 210Ba isformed. A second separation groove 62Ba is then formed to separate asecond inorganic film 50Ba for each of the elements 1Ba (FIGS. 27C to30A). These processes form the light-emitting-element wafer 100B of FIG.33C (FIG. 31).

As described above, according to this embodiment, because the wall plane611Ba of the first separation groove 61Ba is tapered, the first andsecond insulation layers 51Ba and 52Ba may be made of a resin materialwith a low viscosity. This allows formation of the first and secondinsulation layers 51Ba and 52Ba with ease by spin coating, for example.

In the light-emitting element 1B in this embodiment, by adjusting thewidth WB of the bottom plane 612Ba to be in a predetermined size orwider in the first separation groove 61Ba, the reflection layer 53Batilted more than the wall plane 611Ba is formed to reach the bottomplane 612Ba.

This exposes the end plane 532Bs from the second region 532B similarlyto the second embodiment. Herein, the expression of “width in apredetermined size” is assumed to be defined based on the size of theelement 1B in its entirety, or the tilt angle of the second reflectionplane 5312B.

On the other hand, FIGS. 34A to 35C are each a schematic cross-sectionaldiagram for illustrating a manufacturing method in a reference examplewhen a width WC of a bottom plane 612Ca is narrower than a predeterminedsize. FIGS. 34A, 34B, and 34C respectively correspond to FIGS. 32A, 32B,and 32C, and FIGS. 35A, 35B, and 35C respectively correspond to FIGS.33A, 33B, and 33C. In the manufacturing method in this referenceexample, processes are similar to those in the manufacturing method inthe above-mentioned embodiment, and thus are not described in detailagain.

In this reference example, because the width WC of the bottom plane612Ca is narrower than the predetermined size, a reflection layer 53Cais not formed to reach the bottom plane 612Ca (refer to FIG. 35B).Therefore, in a light-emitting element 1C in this reference example, anend plane 53Cs of the reflection layer 53C is exposed from the sidesurface of an optical function film 50C (refer to FIG. 35C).

That is, as shown in FIG. 35C, a light-emitting-element wafer 100C inthis reference example includes a light-emitting layer 20C, and theoptical function film 50C.

The light-emitting layer 20C is a semiconductor, including a first plane201C that includes a first electrode 710C, a second plane 202C isopposing to the first plane 201C and includes a second electrode 720C,and a circumferential plane 203C that connects together the first andsecond planes 201C and 202C. The optical function film 50C includes thereflection layer 53C that covers the second plane 202C and thecircumferential plane 203C, and reflects light coming from thelight-emitting layer 20C by including the end surface 53Cs opposing tothe circumferential plane 203C. The reflection layer 53C includes afirst reflection plane 5311C opposing to the second plane 202C, and asecond reflection plane 5312C opposing to the circumferential plane203C. A first tilt angle between the second reflection plane 5312C and areference plane 201Cs of the first plane 201C is smaller than a secondtilt angle between the circumferential plane 203C and the referenceplane 201Cs.

Such a structure improves heat dissipation of the light-emitting element1C, and allows reflection of light directed to the second plane 202C andthe circumferential plane 203C, thereby enhancing the emission intensitytoward the front of the light-emitting element 1C.

Modified Example

FIG. 36 is a cross-sectional view of a main part of a light-emittingelement 1D in a modified example of the third embodiment, showing thestructure thereof. A second region 532D of a reflection layer 53D inthis modified example is protruded in a direction parallel to a firstplane 201D similarly to the first embodiment.

FIG. 37 is a cross-sectional view of a light-emitting-element wafer 100Din the modified example of the third embodiment, showing a manufacturingmethod therefor, and showing a process of forming an optical functionfilm 50D (50Da). Compared with the manufacturing method for thelight-emitting-element wafer 100 in the first embodiment, themanufacturing method in this modified example is different only in aprocess of forming the optical function film 50D. Therefore, thisprocess is described by referring to FIG. 37, and the remainingprocesses are not described again.

First of all, a first insulation layer 51Da is formed on a wall plane611Da and a bottom plane 612Da of a first separation groove 61Da, and ona second plane 202Db. The first insulation layer 51Da is in the layerstructure including a first film 511Da with no flow properties, and asecond film 512Da with flow properties, for example. The first film511Da is made of silicon oxide such as SiO₂, SiN, TiN, TiO₂, or anyother inorganic insulation materials, and is formed by CVD, sputtering,or others. The second film 512Da is made of an inorganic material withflow properties such as SOG (film-forming SiO₂ coating material), and alight-resistant resin material including polyimide resin, polyesterresin, epoxy resin, or others. Such a second film 512Da is formed byspin coating, coating, spraying, or others.

Thereafter, the first insulation layer 51Da is formed thereon with areflection layer 53Da. For patterning the reflection layer 53Da,similarly to the third embodiment, lifting-off is applicable but is notrestrictive.

The reflection layer 53Da is then formed thereon with a secondinsulation layer 52Da. The second insulation layer 52Da is formedsimilarly to the first insulation layer 51Da.

That is, on a first film 521Da with no flow properties, a second film522Da with flow properties may be formed, for example. The first film521Da is made of silicon oxide such as SiO₂, SiN, TiN, TiO₂, or anyother inorganic insulation materials, for example, and formed by CVD,sputtering, or others. The second film 522Da is made of an inorganicmaterial with flow properties such as SOG (film-forming SiO₂ coatingmaterial), and a light-resistant resin material including polyimideresin, polyester resin, epoxy resin, or others. Such a second film 521Dais formed by spin coating, coating, spraying, or others. Note that thefirst film 521Da is not restrictively made of a material with no flowproperties, but may be made of SOG (film-forming SiO₂ coating material)with flow properties, for example.

Thereafter, the processes similar to the first embodiment manufacturethe light-emitting element 1D (light-emitting-element wafer 100D) ofFIG. 36. In this modified example, an attachment layer may or may not beprovided. When an attachment layer is provided, the attachment layer maybe formed after the first film 521Da of the second insulation layer 52Dais formed, and then the second film 522Da is formed.

With the optical function layer 50D formed as above, a first tilt angleof the second reflection plane 5312D with the first plane 201D is formedsmaller than a second tilt angle of the circumferential plane 203D withthe first plane 201D. As a result, also in this modified example, theemitted light is improved in directivity. Moreover, similarly to thefirst embodiment, with the reflection layer 53D including the secondregion 532D that protrudes to be parallel to the first plane 201D, theemission intensity is enhanced.

Furthermore, the first and second insulation layers 51D and 52D servebetter as the protection films for the light-emitting element as are inthe layer structure with a reduced tilt angle of the second reflectionplane 5312D.

While the present disclosure has been described in detail, the foregoingdescription is in all aspects illustrative and not restrictive. It isunderstood that numerous other modifications and variations can bedevised without departing from the scope of the present disclosure.

In the above embodiments, the second region of the reflection layer isdescribed to protrude in a direction parallel to the circumferentialplane or the first plane. The direction of protrusion is notparticularly restrictive as long as the direction is toward the outsideof the light-emitting layer.

Also in the above embodiments, the optical function film is in the layerstructure including the first insulation layer, the reflection layer,and the second insulation layer. This structure is not restrictive aslong as the optical function film includes the reflection layer.

Also in the first embodiment, the inorganic film is described to beformed on the first plane. This is not restrictive, and thelight-emitting layer may not include the inorganic film. As to thelight-emitting elements in the second and third embodiments, on theother hand, the inorganic film may be formed on the first plane.

Also in the above embodiments, the first plane is described to be in theconcave-convex structure. This is not restrictive, and the first planemay not be in the concave-convex structure. Moreover, in the firstembodiment, the inorganic film is described to be in the concave-convexstructure to conform to the first plane, but this is not restrictive. Asin the modified example of the third embodiment, for example, even ifthe first plane is in the concave-convex structure, the inorganic filmmay not be in the concave-convex structure.

Also in the above embodiments, the first plane is described to be formedto be larger than the second plane, but this is not restrictive. As anexample, the light-emitting layer may be substantially in theparallelepiped shape, and the first and second planes may besubstantially in the same size. Alternatively, the second plane may beformed to be larger than the first plane. The first and second planesare not restricted to be in the rectangular shape, and may be in theoval or circular shape, for example.

Also in the above embodiments, the light-emitting layer is described toemit red light. This is not restrictive, and the light-emitting layermay emit blue or green light. If with the light-emitting layer emittingblue light, for example, a semiconductor material for use is exemplifiedby GaN (gallium nitride).

Also in the above embodiments, the light-emitting element is describedto be an LED, but may be a semiconductor laser, for example. Theelectronic apparatus is not restricted to a display apparatus, and maybe lighting fixtures such as tail lamps of vehicles, inspectionapparatuses mounting LEDs or semiconductor lasers, or pickup devicesavailable for writing or reading of optical disks, for example.

Also in the above embodiments, the light-emitting-element wafer isdescribed to include the attachment layer.

This is not restrictive, and the attachment layer may not be provided.

The present disclosure may be also in the following structures.

(1) A light-emitting element, including:

a light-emitting layer configured to include a first plane with a firstelectrode, a second plane with a second electrode, and a circumferentialplane connecting the first and second planes, the second plane beingopposing to the first plane, and the light-emitting layer being made ofa semiconductor; and

an optical function film configured to include a reflection layer beingable to reflect light coming from the light-emitting layer, thereflection layer being provided with first and second regions, the firstregion covering the second plane and the circumferential plane, thesecond region protruding from the first region to an outside of thelight-emitting layer to expose an end plane thereof.

(2) The light-emitting element according to (1), in which

the optical function film further includes

-   -   a first insulation layer formed between the light-emitting layer        and the reflection layer, and    -   a second insulation layer formed on the reflection layer.        (3) The light-emitting element according to (1) or (2), in which

the second region protrudes in a direction parallel to the first plane.

(4) The light-emitting element according to (1) or (2), in which

the second region protrudes in a direction parallel to thecircumferential plane.

(5) The light-emitting element according to any one of (1) to (4),further including:

an inorganic insulation film configured to cover the first plane.

(6) The light-emitting element according to any one of (1) to (5), inwhich

the first plane is in a concave-convex structure.

(7) The light-emitting element according to any one of (1) to (6), inwhich

the first plane is formed to be larger than the second plane.

(8) The light-emitting element according to (7), in which

the first region includes first and second reflection planes, the firstreflection plane being opposing to the second plane, the secondreflection plane being opposing to the circumferential plane, and

the second reflection plane forms a first tilt angle with the firstplane, and the circumferential plane forms a second tilt angle with thefirst plane, the first tilt angle being smaller than the second tiltangle.

(9) The light-emitting element according to any one of (1) to (8), inwhich

the light-emitting layer emits red light.

(10) The light-emitting element according to (9), in which

the semiconductor includes at least any one of an AsP compoundsemiconductor, an AlGaInP compound semiconductor, and a GaAs compoundsemiconductor.

(11) A light-emitting-element wafer, including:

a support substrate; and

a plurality of light-emitting elements each configured to include

-   -   a light-emitting layer configured to include a first plane with        a first electrode, a second plane with a second electrode, and a        circumferential plane connecting the first and second planes,        the second plane being opposing to the first plane, and the        light-emitting layer being made of a semiconductor, and    -   an optical function film configured to include a reflection        layer being able to reflect light coming from the light-emitting        layer, the reflection layer being provided with first and second        regions, the first region covering the second plane and the        circumferential plane, the second region protruding from the        first region to an outside of the light-emitting layer to expose        an end plane thereof, and

to be arranged on the support substrate, the support substrate beingopposing to the second plane with the optical function film beingsandwiched therebetween.

(12) The light-emitting-element wafer according to (11), furtherincluding:

an attachment layer configured to attach the support substrate and theplurality of light-emitting elements.

(13) An electronic apparatus, including:

a substrate formed with a driving circuit; and

at least one first semiconductor light-emitting element configured toinclude

-   -   a light-emitting layer configured to include a first plane with        a first electrode connected to the driving circuit, a second        plane with a second electrode connected to the driving circuit,        and a circumferential plane connecting the first and second        planes, the second plane being opposing to the first plane, and        the light-emitting layer being made of a semiconductor, and    -   an optical function film configured to include a reflection        layer being able to reflect light coming from the light-emitting        layer, the reflection layer being provided with first and second        regions, the first region covering the second plane and the        circumferential plane, the second region protruding from the        first region to an outside of the light-emitting layer to expose        an end plane thereof, and

to be arranged on the substrate, the substrate being opposing to thesecond plane with the optical function film being sandwichedtherebetween.

(14) The electronic apparatus according to (13), in which

the first semiconductor light-emitting element and other firstsemiconductor light-emitting elements emit red light,

the electronic apparatus further includes

-   -   a plurality of second semiconductor light-emitting elements that        emit blue right, and    -   a plurality of third semiconductor light-emitting elements that        emit green light, and

the first, second, and third semiconductor light-emitting elements arearranged on the substrate.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A light-emitting element, comprising: alight-emitting layer configured to include a first plane with a firstelectrode, a second plane with a second electrode, and a circumferentialplane connecting the first and second planes, the second plane beingopposing to the first plane, and the light-emitting layer being made ofa semiconductor; and an optical function film configured to include areflection layer being able to reflect light coming from thelight-emitting layer, the reflection layer being provided with first andsecond regions, the first region covering the second plane and thecircumferential plane, the second region protruding from the firstregion to an outside of the light-emitting layer to expose an end planethereof.
 2. The light-emitting element according to claim 1, wherein theoptical function film further includes a first insulation layer formedbetween the light-emitting layer and the reflection layer, and a secondinsulation layer formed on the reflection layer.
 3. The light-emittingelement according to claim 1, wherein the second region protrudes in adirection parallel to the first plane.
 4. The light-emitting elementaccording to claim 1, wherein the second region protrudes in a directionparallel to the circumferential plane.
 5. The light-emitting elementaccording to claim 1, further comprising: an inorganic insulation filmconfigured to cover the first plane.
 6. The light-emitting elementaccording to claim 1, wherein the first plane is in a concave-convexstructure.
 7. The light-emitting element according to claim 1, whereinthe first plane is formed to be larger than the second plane.
 8. Thelight-emitting element according to claim 7, wherein the first regionincludes first and second reflection planes, the first reflection planebeing opposing to the second plane, the second reflection plane beingopposing to the circumferential plane, and the second reflection planeforms a first tilt angle with the first plane, and the circumferentialplane forms a second tilt angle with the first plane, the first tiltangle being smaller than the second tilt angle.
 9. The light-emittingelement according to claim 1, wherein the light-emitting layer emits redlight.
 10. The light-emitting element according to claim 9, wherein thesemiconductor includes at least any one of an AsP compoundsemiconductor, an AlGaInP compound semiconductor, and a GaAs compoundsemiconductor.
 11. A light-emitting-element wafer, comprising: a supportsubstrate; and a plurality of light-emitting elements each configured toinclude a light-emitting layer configured to include a first plane witha first electrode, a second plane with a second electrode, and acircumferential plane connecting the first and second planes, the secondplane being opposing to the first plane, and the light-emitting layerbeing made of a semiconductor, and an optical function film configuredto include a reflection layer being able to reflect light coming fromthe light-emitting layer, the reflection layer being provided with firstand second regions, the first region covering the second plane and thecircumferential plane, the second region protruding from the firstregion to an outside of the light-emitting layer to expose an end planethereof, and to be arranged on the support substrate, the supportsubstrate being opposing to the second plane with the optical functionfilm being sandwiched therebetween.
 12. The light-emitting-element waferaccording to claim 11, further comprising: an attachment layerconfigured to attach the support substrate and the plurality oflight-emitting elements.
 13. An electronic apparatus, comprising: asubstrate formed with a driving circuit; and at least one firstsemiconductor light-emitting element configured to include alight-emitting layer configured to include a first plane with a firstelectrode connected to the driving circuit, a second plane with a secondelectrode connected to the driving circuit, and a circumferential planeconnecting the first and second planes, the second plane being opposingto the first plane, and the light-emitting layer being made of asemiconductor, and an optical function film configured to include areflection layer being able to reflect light coming from thelight-emitting layer, the reflection layer being provided with first andsecond regions, the first region covering the second plane and thecircumferential plane, the second region protruding from the firstregion to an outside of the light-emitting layer to expose an end planethereof, and to be arranged on the substrate, the substrate beingopposing to the second plane with the optical function film beingsandwiched therebetween.
 14. The electronic apparatus according to claim13, wherein the first semiconductor light-emitting element and otherfirst semiconductor light-emitting elements emit red light, theelectronic apparatus further includes a plurality of secondsemiconductor light-emitting elements that emit blue right, and aplurality of third semiconductor light-emitting elements that emit greenlight, and the first, second, and third semiconductor light-emittingelements are arranged on the substrate.